Instruction: Analyze a question and its supporting document. Predicting answerability based on the information provided in the document. Output yes if the document contains relevant information to answer the question, otherwise output no.

Input:
Question: i had sram x4 on my trek marlin, badly i broke it............i see this  exactly the same name, but  long cage, is this gonna fit my  bike? I DON'T KNOW ABOUT LONG CAGE OR SOMETHING, NEITHER THE WEBSITE SAYS ABOUT IT, JUST SRAM X4
Document: I wish Amazon would sell the SRAM X3 to X4 rear derailleur in the mid cage length but they don't.
I bought this to replace an old Shimano Alivio rear derailleur.I'm sure this rear derailleur works fine on many different bikes. SRAM makes good stuff. Funny thing is it would not fit on my bike. I had a 1999 Trek 800 sport which is a totally typical, bone stock, CrMo tube, hardtail mountain bike.
SRAM has come a long way in the last 10 years and their bike components are top notch. I run nothing but SRAM drivetrain now (X.5, X.7, and X.4 on my sons bike) and love that I can adjust and forget! Even though this is the bottom of the product line rear derailleur is it reliable and strong.Just an FYI for the reviewer above and for anyone reading. SRAM's rear 1:1 derailleurs DO NOT have a rear cable adjuster like Shimano.
In the product description it mentions that this derailleur can be used with a 9-speed cassette BUT IT DOES NOT. I'm currently running it with an SRAM shifter set with the same actuation ratios but no matter how much I tighten/loosen the cable, I can't get a smooth transition through all nine gears. It lags around the fourth/fifth and doesn't reach the largest cog.It's not a bad derailleur at all, I bought it for the road bike i assembled from the frame up.
I also purchased an 8-speed sram x4 trigger shifter and installed both at the same time. This setup shifts grreat. Quick, crisp shifting.
I am upgrading the drivetrains on my children's bikes. I got this initially for my son's 20" Hotrock to be paired with a X3 trigger shifter. I discovered  that the long cage is too long for a 20" wheel (the bottom of the cage is only an 1 1/2 inch off the ground).I changed my plans and will use it on my daughter's 24" Hotrock instead. For my son I ended up with Shimano Altus rear derailleur with the Acera SL-M310 trigger shifter.
Used this on my girl friend's mountain bike that I am building... found some Sram shifters and needed the derailleur to match.
I swapped my daughter's Novara 7 speed from cheap Shimano derailleur to this SRAM X4. It took about 15 minutes. I've also changed her bike's twist shifters to the SRAM X3. Everything works great. It shifts fast and solid.
These derailleurs are awesome. Cheap (only in price), fairly lightweight, reasonably durable, GOOD shifting and EASY to set up. If you keep these clean and keep your chain looked after they'll last a long time. SRAM makes quality stuff!
Sofar so good. I installed the Sram X 4 on my bike which is a seven speed casette. After some tweeking it shifts on command. I give it a five star rating for its look  how well it works and ease of ajustment. I'm not a serious MTB rider but I am 300lbs  ( and loosing the weight) I  hit the up hill climbs with a heavy foot. It shifts well under that condition.
Answer: no