Product review (3 stars): It's OK
It worked out. I had to attach the screen at the opening with some sheet metal screws to hold it in. The slightest touch and it pops out. The screws fixed that. More important is the fact that the flashing is really too small. Careful installation and sealing gets around that but a TEE stack from one of the big box stores would likely have been the better choice. I also bought the specific collar for this part and it went on easily and chalking was easy.