This bucket lid insert requires a gasket to make a vacuum seal.
Dimensions:
Diameter – 7.25″
Thickness – 3/16″
Port size – 11/16″ (1/2″ milk tubing will fit if stretched)
Complete basic bucket lid
https://simplepulse.com/products/bucket-lids?_pos=10&_sid=3cbc9f75a&_ss=r