This is a set of air locks, which are manufactured with premium PP material, and practical enough to use. The kit serve as versatile fermenting equipment, for a variety of purposes, such as preserve foods, ferment of cabbage, pickles, sauerkraut, grape juice and so on, or making , , . Features -Color: Assorted color. -Material: PP. -Size: About 12.00X4.00X4.00cm/ 4.72X1.57X1.57in. - Manufactured with premium PP material, and practical enough to use. - Just drill a suitable hole on your lid (follow the size of air valves), then insert the black grommet into the lid hole, place the tapered tip of the into the grommet hole to seal the . - Black grommets are made of premium materials, safe, and soft, can serve for a long time use . - These simple tools, the , not only makes fermenting easier but aids in producing safe and healthy food. - The kit serve as versatile fermenting equipment, for a variety of purposes, such as preserve foods, ferment of cabbage, pickles, sauerkraut, grape juice and so on, or making , , . Package list: 3 x Air Locks 3 x Silicone Plugs