Package includes: you will receive 10 pieces of silicone grommets and 5 pieces plastic airlocks, enough for your use and replacement material: these airlocks are made of pp plastic, the airlock grommets are made of silicone, durable and soft, safe for your use, can for a long time use Keep good seal: easy to use, just drill a suitable hold on your fermenter lid ( the size of air valve), then use the black grommet insert into the lid hole, place the tapered tip of the airlock into the grommet hole to make a good seal Convenient to clean: easy to clean with practical design, the airlock can be disassembled, just use a small brush to clean completely, it can in bleach water to disinfect Main function: the airlock kit as versatile fermenting equipment, for a of purposes, such as preserve foods, ferment of cabbage, , sauerkraut, grape and so on, or making beer, wine, mead size:Seal ring inner diameter: 8mm Material:Plastic + Silicone colour:As Shown Package Contents: 5 x Three-piece check valve 11.5cm 10 x seal ring Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.