Safe material: The 6 piece fermentation airlocks are made of pp plastic, not cause any harm to the human body, nor any pungent smell, airlock grommets are made of silicone, and soft, safe for your using Completely sealed:Just drill a 3/8 inch hold on your fermenter lid ,then use the black grommet insert into the lid hole,perfect for allowing fermentation gases to escape without allowing oxygen to enter,can make a good seal Airlocks for fermenting set with 6 pieces plastic airlocks and 24 pieces silicone grommets,it is strong and for your long time use Widely use: the airlock kit for brewing craft beer, wine, sauerkraut, , hard cider, fruit wine, rice wine, carrots and ginger, ,tastes very good Easy to clean:The fermentation airlock easy to clean,this airlock can be separately taken out and cleaned,it can be easily cleaned with hot water or a simple detergent, very convenient and simple, Weight: 0.31636334597 Pounds, Manufacturer: Jaywool