Product review (5 stars): It worked with some help...
We have a sub-zero 600 series. Installation was fairly easy as a two person job.  A couple things I wish we'd known ahead of time: 1) you either need to heat it to get the wrinkles out before putting it on, or be prepared to stand there with a hair dryer to warm and then work them out. It's not hard, but takes some time. 2) It's probably not going to seal like you expect at first.  We ended up doing two things to get the seal to seal like it should a) petroleum jelly on the seal where it touches the refrigerator body and b) holding it shut with a bungie and broom handle (or anything heavy enough to push and hold it tightly)

We had a a few days thinking we had done it wrong, but after we rigged it to be firmly pushed shut all the time (we had it so we could easily open it to use it too), it took about 2 days with the jelly & pressure and it started sealing like a champ.

It turns out after years of use, the old seal adapts to your frig (and anything that's not perfect) - the new one needs some help to adjust and settle in.