This item is a plastic one piece lid for wide mouth jars (Ball, Kerr, etc). It can be autoclaved (sterilized) and used for grain, agar, or liquid culture (LC) jars.
The lid is modified with a 1/4″ hole covered with a filter for gas exchange and a self healing injection port. The port location is easily identified by a mound (see photo below).
These are made in house and are the same ones MMM uses to prepare grain, LCs, and distilled water for spore syringes.
Ask for discounts on 5 + 10 packs!