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The KING® F9 SPEEDBACK™ ONE Length™ irons are engineered to simplify your game by reducing variables in your swing to increase accuracy and consistency.


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KING F9 One Length Irons
  • What IS IT

    Each ONE Length iron is designed to match 7-iron length and weighting to deliver consistent feel, trajectories and distance gapping through the set.


    Ideal for 5 to 25 handicaps with moderate to faster swing speeds seeking a forgiving distance iron with great feel. ONE Length allows you to swing every iron like it's your trusty 7-iron.

  • Why we made it

    The Cobra ONE Length irons are inspired by the revolutionary swing philosophy pioneered by Bryson Dechambeau on Tour. A ONE Length configuration allows you to use one repeatable setup and swing through the set, resulting in more consistency and accuracy.

King F9 One Length Irons Grass Laydown
One Length

One Length.
One Swing.

Engineered using matching 7-iron length and weight specifications, a ONE Length configuration simplifies your game by reducing variability in your setup and swing for increased consistency.

Track And Tune
Track And Tune

Wider Sole Widths

Wider soles in the 4-6 irons lower the club's center of gravity to deliver hybrid-like distance, launch and forgiveness with iron-like precision.

F9 Driver Aero

Progressive Shaft Weighting

Premium aftermarket KBS shafts in three different weights (KBS Tour 80 in the 4-6i, KBS Tour 90 in the 7-9i, and KBS Wedge in the GW-SW) optimize launch, feel and trajectory through the set.

F9 Driver Back Tungsten Weight


Much like a wide-body kit adds to the stability of a racecar, SPEEDBACK shaping utilizes a belt of steel that adds mass low and wide, creating a lower, deeper CG that maximizes ball speed, launch and carry while maintaining a conventional sole width.

SPEED Tuned Performance

Forged E9 PWRSHELL Face

An E9 variable thickeness face design is 1.8mm at its thinnest point, expanding the SWEET ZONE to increase distance on off-center hits. A forged PWRSHELL design features a deep undercut sole with a 1.2mm internal Speed Channel that returns more energy to the ball for higher launch and faster ball speeds.

F9 Driver Aero

High MOI Design With Tungsten

SPEEDBACK adds more mass low and wide compared to a conventional game improvement iron. 33 grams of tungsten is combined in the heel and toe in the 4-7 iron, increasing MOI for maximum stability, higher inertia, and substantial improvements in ball speed, distance and forgiveness.

F9 Driver Back Tungsten Weight

Best In
Class Feel.

A 3-piece multi-material medallion combines aluminum, TPU (Thermoplastic Polyurethane) and acrylic foam. These lightweight materials damp vibrations to promote a softer, more responsive feel that is not normally found in a game improvement iron.

KING f9 Speedback


CNC milling is a highly precise manufacturing method that is typically only found in forged player's irons. This process allows us to create perfectly flat faces, and precise lofts and groove shapes in every iron we manufacture.

CNC Milled face driver

spin technology.

Progressive groove shapes are CNC milled into each face to optimize spin performance in the long irons, mid-irons and wedges.



CNC milled V-grooves reduce spin for increased distance and flight time.



CNC milled U-Grooves optimize spin for improved control and accuracy.



Tighter-spaced, U-grooves increase spin for improved precision around the green.

hosel lengths.

Shorter hosels in the long irons (4-6) lower the CG to increase launch and distance, medium hosels in the mid irons (7-9 iron) create a gradual transition from the long irons and taller hosels in the wedges (GW-SW) raise the CG to promote control and accuracy.

CNC Milled face driver


COBRA CONNECT grips feature embedded sensors that work in conjunction with the Arccos Caddie mobile app - the award-winning connected golf system that helps players of all skill levels make smarter, data-driven decisions and shoot lower scores.

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Cobra Connect Logo

Automatic Shot Tracking

Receive real-time data for all aspects of your game.

True Club Averages

True Club Averages

Select the right club for every shot with SMART DISTANCE insights.

Advanced Analytics

Advanced Analytics

Use detailed performance breakdowns to guide equipment choices, practice & more.

Golfs Smartest Caddy

Golf's Smartest Caddy

Trust artificial intelligence to reveal your best strategy tee to green.


With your purchase of a set of KING F9 SPEEDBACK irons, you will receive your choice of FREE additional Arccos Caddie Smart Sensors or COBRA CONNECT grips so you can connect your entire bag (from your driver to putter) and experience your first set of Smart Clubs.

Receive game changing insights FREE for 3 months, then subscription rates apply.

How to redeem:

  1. Purchase a set of KING F9 SPEEDBACK irons.
  2. Download the Arccos Caddie app on your mobile device.
  3. Follow the instructions through the Arccos Caddie app to redeem your FREE Cobra Connect grips or Smart Sensors.

Download Arccos Caddie:

Arccos Caddie
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Track And Tune



  • Steel: 5-GW
  • Graphite: 5-GW

Iron Loft Lie
(Graphite & Steel)
Standard Length
(Graphite & Steel)
Swing Weight
Swing Weight
4 19.5° 65.0° 6.0 37.50" 37.25" C9 D1 RH/LH*
5 22.5° 64.5° 5.1 37.50" 37.25" C9 D1 RH/LH*
6 25.5° 64.0° 4.2 37.50" 37.25" C9 D1 RH/LH*
7 29.5° 63.5° 3.2 37.50" 37.25" C9 D1 RH/LH*
8 34.0° 63.0° 2.6 37.50" 37.25" C9 D1 RH/LH*
9 39.0° 62.5° 2.0 37.50" 37.25" C9 D1 RH/LH*
PW 44.0° 62.0° 1.5 37.50" 37.25" C9 D1 RH/LH*
GW 49.0° 61.5° 1.0 37.50" 37.25" C9 D1 RH/LH*
SW 54.0° 61.5° 1.0 37.50" 37.25" C9 D1 RH/LH*

*LH Custom Only


ATMOS 6 ONE Length
ModelFlexShaft WeightKick PointTrajectorySpinTip Diameter
Fujikura ATMOS 6 ONE Length Stiff 66g Mid Mid Mid 0.370
Fujikura ATMOS 6 ONE Length Regular 63g Mid Mid Mid 0.370
Fujikura ATMOS 6 ONE Length Lite 62g Mid Mid Mid 0.370

KBS Tour 80
ModelFlexShaft WeightKick PointTrajectorySpinTip Diameter
KBS Tour 80 Stiff 100g Mid-Low Mid-High Mid 0.370
KBS Tour 80 Regular 100g Mid-Low Mid-High Mid 0.370

KBS Tour 90
ModelFlexShaft WeightKick PointTrajectorySpinTip Diameter
KBS Tour 90 Stiff 102g Mid-Low Mid-High Mid 0.370
KBS Tour 90 Regular 95g Mid-Low Mid-High Mid 0.370

KBS Wedge
ModelFlexShaft WeightKick PointTrajectorySpinTip Diameter
KBS Wedge Stiff 120g Mid-Low Mid-High Mid 0.370
KBS Wedge Regular 110g Mid-Low Mid-High Mid 0.370


COBRA Lamkin Crossline Connect

COBRA Lamkin Crossline (58+) Connect - Blue / Red

Customer Reviews 10 item(s)

So far so good.
Review by Joe - 3/18/2019

Weather has not permitted anything other than two trips to the range, where my contact felt solid and dispersion was tight. As far as the "one length", it simply felt totally natural. Felt like all clubs should be made that way!!!

Cobra King F9 One Length Irons are the best irons I have ever owed!
Review by Jeremy - 3/10/2019

First of all, I have to say that I never do club reviews. That being said, after hitting and playing with these new Cobra King F9 One Length irons I have to say that I am totally impressed and blown away. I have tried another company’s “single length” irons in the past and I didn’t really like them, so I was a bit nervous when I decided to pull the trigger on buying these clubs. I am so glad I did though.
I have a handicap index of 4.1 and have been playing golf for about 23 years now. Like many of you, I have tried just about everything out there trying to find that one “magic” thing that would help me hit the ball more consistent. Now, I am not saying these clubs are magical, but what I am saying is that since switching to these clubs they have greatly helped me improve my accuracy and my confidence over the ball.
One of the first things that I noticed is the lower lofted clubs (4,5,6,7) are a bit chunkier then what I was expecting, but after hitting them I know why. These things fly far and high. The height is the one thing that shocked me the most. I have read reviews and tried other brands and I did notice how low the 4 and 5 irons flew in those sets and I was worried that it would be the same in this one, but to my pleasant surprise that is not the case at all. When I strike the ball well the 5 irons take off high, goes straight, and far. The more mass and heavier weights in the lower lofted clubs makes it so much easier to launch the ball high with these clubs compared to other brands I have tried.
The higher lofted clubs (8, 9, PW, GW, SW) look more like players clubs, with less mass seen at address. It gives you the confidence that you can hit these clubs closer to the hole with ease. The ball comes off nice and high and stops on a dime on the green. It allows me to take on more flags and know that when it lands it will stop shortly after.
Now I won’t tell you that the change from variable lengths and single lengths was quick and easy. There is some adjustment period that is needed. It is mainly in that 3-inch gap between your ears though. At first because the 4 and 5 irons looked so short, I felt like I had to swing super hard to get the numbers that I needed, but that was the wrong approach. If you can just convince yourself to swing those clubs with your normal swing, you will get amazing results. The reverse was true with the higher lofted clubs. I felt like because they were longer, I was going to fly every green I looked at, but because Cobra did an amazing job adjusting the head weights in these clubs the ball goes the yardages I want and lands soft on the green. Once you can convince yourself to swing normal you will have clubs that allow you to set up the same way and swing the same way. The golf game becomes more enjoyable and repeatable with these clubs.
If you are on the fence about the clubs, don’t be. After you are able to get over the mental block that comes with changing your thought process on clubs and their lengths, you will start hitting the ball better, with more frequency. Good luck and hit them well!

F9's One Length Really Performs
Review by David - 3/5/2019

I bought F7's when they came out and I enjoyed them. I did find they had technical issues that were problematic. When I was ready for new clubs this year I called and talked to Cobra about my problems with F7's and was thrilled to have them recognize and address all the difficulties I encountered playing them for 2 years. I ordered the F9"s and from the very first ball I struck with them it was clear they had addressed all of my issues. These irons are fantastic. I absolutely love them and look forward to playing more golf this year with them. They are consistent in stability through the set, the flex is consistent, the feel is great. I don't know what more to say. Try them. I bet you will love them too.

More fun and consistency
Review by Ruud - 3/4/2019

I was always struggling with my long irons to get these consistent. This is now past history as these single length irons make life so much easier. Just bought them, played only once and already this is making a huge difference.

Blown away
Review by Mr. E - 2/21/2019

These irons blew away my expectations. I had been playing a premium brand set recently fitted to my swing, but decided I needed to try out the one length philosophy. Not only do I love the single length aspect of the set, but the look at address is very charming, and a pure strike has a sublime feel. Thanks Cobra!

Golf has been simplified
Review by Shane - 2/19/2019

These are game changers for us regular folk that don't have the time to master all the different ball positions and swings for variable length clubs. Finally i have confidence in getting a good strike with every club because they're all the same!

Beautiful clubs with a wonderful feel. Before I got them I had read that some people are concerned with being able to get the 5i airborne. All i can say is don't be! I have a medium swing speed and the ball just explodes off the face and goes the same height as my other 5i.

My days of spending hours at the range trying to groove my swing are over. All my range money can now go towards playing actual golf!

Love these clubs
Review by GrumpyGolfer - 2/19/2019

I am never going to be a scratch golfer. Just someone who loves the game. What I love about these clubs is that I feel like I have a chance to make par on every hole. I’m no longer struggling to hit a 6-4 iron and felt like my play with the 8-G didn’t suffer at all. I’ll never hit anything but one length clubs again.

Great Iron
Review by JR - 2/15/2019

Just for my own knowledge I tried the One Length 4 iron to gain more consistency in my longer irons. Why did I not know about this sooner? I left my longer 4 in the bag and grab the One Length 4 when I’m in the situation for this iron. I’m concidering the entire set of One Length Irons now. Sorry T M. I found a better way to get there.

Beyond Expectations
Review by Terry - 1/29/2019

Loved them the first time I picked them up. Much more confidence with the longer irons, and even the short irons took little time to adjust to. I am sold on the concept, and the quality of these clubs is great. Love the feel of a well struck ball.

Quickly falling in love with the F9 one lengths!
Review by Lgnir - 1/27/2019

Back in the early 90's I almost bought a set of Tommy Armour EQL's as I liked the idea behind one length irons. Fast forward 29 years and my main purpose was to go to one plane so it's easier on my back.

I'm lucky enough to have a hitting bay in my garage and a SkyTrak, so I am able to make some good comparisons of the F9's to my previous Callaway Big Bertha OS irons.

My first impression was the great feedback I received from these irons. I can easily feel if I am low, high, right or left of the center of the clubface. Although it took about 4-6 hours to get used to the one lengths, once I did, I was amazed at the distances I was getting, and how tight my dispersion circles were compared to my previous irons.

The best thing? My club gaps are WAY more consistent now! From gap wedge through 5 iron I have about a 10-12 yard gap between each club!

I am having a little difficulty learning to hit the one length 4-hybrid, but I just need to practice with it some more.

If you are thinking about trying one length, give the F9's a try. I think you will like them. From the KBS shafts, to the chrome on the clubheads, I think Cobra has made a really high quality iron. I am extreamly pleased with my purchase!

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