Best PTFE gasket?

[stillanoob]

Howdy Folks,

Working on my thumper. I actually bought a piece of my still for the first time, the thumper fitting. Looks really well made. Thing is, the sent it with a silicone o-ring for a gasket. I am using a 15.5 gallon keg for the thumper. I see a lot of 2" gaskets out there, anyone have a preferred brand, type or supplier?

Thanks!