Attached is a link with the winter plugs.
Pool and Spa Winter Plugs to Protect Lines from Freezing
I closed the pool yesterday and there are 4 returns on each side (House and Yard). The steps have a special thread, so I used the black rubber plugs with the wing nut. I used the threaded winter plugs and saw some small bubbles (air leaks) as it was very apparent (Thanks TFP as water is so crystal clear).
I tightened them a little more and there still was a leak. I did not use Teflon Tape as there was an O-Ring (unlike Skimmer Gizmo's). Customer Service is telling me that the O-Ring is what seals everything. Unfortunately these did not work and I used the black plugs, which of course are not leaking. They claim that the threads are stripped, which I doubt all 8 of them are bad.
Question: Has anyone ever used this type, and what experience have they had? Thank you.