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 just bought a Chamberlain WD962KEV to be installed with an 8 foot door.  Do I need this extension kit?
Document: The extension kit works great on a 10 foot door. Easy to install and directions for changes to original instructions clear.
It would of been nice if there were instructions with the kit to tell you that you needed to remove not one, but two sections from the existing seven foot rail assembly that came with the opener. After discovering this with the first opener, the second one went smoothly. I don't know why the guy in the previous reviews had problems with the door sensor wires being short. The wires were plenty long enough to handle a ten foot door that I was able to make it look like a professional installation.
This installed easily to make a regular 7' garage door opener work for my 10' door. My only concern is that the unit is at the end of the tension adjustment when first installed so I don't quite know what I'll do as the belt ages and stretches.
Needed extension kit for my garage door openers. They arrived fast and in good condition. The only concern I had was some of the instructions were not clear enough. After some time rereading and moving parts around, we got them up and work perfectly.
Came right on time. Had a little freakout however when we installed the extension kit. We didn't realize that you had to remove some of the bars that came with the opener. My advice is to FULLY read the instructions. Other than that, had no problems and worked great.
This unit is compatible with the Craftsman line of belt driven garage door openers. I believe that the craftsman units are rebranded versions of the Chamberlain's. Specific for my application, the rail extension, belt attachments and wire extensions were all interchangeable.Despite the sparse product description, the extension kit was very complete and included everything I needed to extend the original 7' Craftsman.
Came with instructions... Works perfectly. Looks exactly like the kit that I ordered from craftsman for my other door other than the print on the box.
Excellent product!! Easy installation every thing we hoped for. My husband installed it  him self, only took a weekend of his time.
This is a 2' extension which means the door is 2' taller, and the motor is 2' further from the wall. This means each wire needs to be 4' longer, however a longer wire is not included, and the instructions say to use the original wires. On my installation both sensor wires and the switch wire were too short. You can make it work by running the wire directly on a diagonal, but this looks bad.
Just make sure you know to take off the additional rails from the original kit. You don't add all of them plus the extension kit. Other than that, this was easy to install and has worked amazingly!
Answer: yes