Buy “Chamberlain 8 inch Chain Drive Extension Kit 7704CB – Garage Door Hardware -” Online
this gets a big fat ZERO!! this is not part# 7704cb it is 7708cb and this will not fit and is not interchangeable!!!! the description is even all wrong for the part! Check it out!
From the Manufacturer Have an oversize garage door? The vast majority of garage doors are 7 feet tall, but if yours is 8 feet high and you plan on using a Chamberlain Chain Drive Garage Door Opener, this T-Rail extension kit is the perfect accessory! This kit provides all the necessary materials to allow your off-the-shelf garage door opener to function perfectly with your custom door! Remember, these models are only appropriate for Chain Drive Garage Door Openers. For Screw Drive openers, look up Model No. 7706CB.
Chamberlain 8 inch Chain Drive Extension Kit 7704CB Review
This fits your .
Enter your model number
to make sure this fits.
Includes all the parts needs to install on larger 8′ doors
Works will all Chamberlain Screw Drive garage door openers