Spring Creek Mushrooms Self Healing Rubber Injection Ports (12 peices) 13mm Rubber Bottle Stoppers (Steam Sterilization Safe) for Sealing 1/4 inch or 7mm Opening

Rubber Bottle Stoppers Self Healing Injection Ports for Mason Jar Lids ... Use 1/4 inch drill or punch for tight seal. Autoclave/sterilizer safe. Fits 13 mm bottle with 7mm or 1/4 inch opening. We use for liquid culture and BRF jars, test tubes and bottles. Its smaller size makes it more sanitary and easy to use and easier than drilling those big holes for the larger stoppers Great for liquid culture, BRF Jars, injection, Supplemented substrate jars, Grain Masters