On Tue, 25 Jun 2013 07:09:59 -0700, Oren wrote:

That is an insert for the 3/4 PVC. The poly is pushed in. It can be
pulled out, but can be a little difficult. Twist and pull. Twist and
pull.

You weren't kidding it was hard to pull out (the Chinese finger lock
description is apropos). I had to pull hard, with pliers:

http://www1.picturepush.com/photo/a/...g/13410474.jpg

Of course, I forgot to think ahead; so, um .... I now have a brand
new 80psi leak in my plumbing!

http://www3.picturepush.com/photo/a/...g/13410476.jpg