Long story! We have a detached single garage. We're renting and never did get the key for the quick-release mechanism. We also lost the only remote we had so had no access to the garage!!!
A locksmith was able to get us in, but that meant the current mechanism had to be drilled thus destroying it.
Not really knowing how to replace it I bought 2 quick-release systems.
It took us a while to get around to replacing the mechanism, but the first one we opened worked perfectly. It's super simple really.
As such, this "Universal by Chamerlain" has never been opened. I bought it on Amazon and missed the return window (darn!). My loss if your gain. Get this at a discount!