Here is a review from an installation done May 30. 5 stars. Its what I invented Critter Quitters to do, amongst other things like keeping animals out of toilets and making a roof look good.
I used this to cover up a botched lead flashing installation job. It completely covered a 1 1/2 in vent pipe that was covered by lead flashing and it fit just fine. If it doesn’t slide all the way down onto your pipe, you need to trim the bottom to match the pitch of your roof and allow it to actually rest on the top of the pipe. This is easily done in a few seconds with a hacksaw or miter saw. Then tighten a few screws and you’re done. Climbing on the roof is definitely the hardest part of the installation job!