[rodneym]

Patrickt,

On the thread you linked, your last post/picture shows what I believe most of us use.
BUT, Stant sells caps rated at the same pressure, that say 'Vented'. When I pick it up, that little button (lower most part of the cap) just hangs loose about a quarter inch. If both caps are placed upside down like your pic, you won't see the difference.
The caps that don't say 'Vented' have the button that touches the smaller rubber piece and is slightly spring loaded.
I understand how the expansion system works but I don't necessarily see how the button being spring loaded affects use, all I know is that the 'Vented' caps have a dangling button.

Am I in the Twilight Zone on this?

Rodneym