Use this kettle plug kit to plug a 13/16" hole in a kettle, if you're not using the hole.
The metal parts are all 304 stainless steel, and the o-ring is heat resistant silicone, so the whole thing is food grade and sanitary.
Three Piece Airlock
Star San Sanitizer - 16 fl oz (473 ml)
Cascade Hop Pellets - 1 oz (28 g)
Citra Hop Pellets - 1 oz (28 g)