Features:Made of and long lasting silicone, the airlock grommet with good hermetical sealing performance fits most airlock and you can use the airlock grommet to turn jars into drinking bottles. Various application: This airlock grommet fits well with most types of airlocks and plastic buckets lids and straws. It is much convenient to make your own airlock lids for fermenting with our useful product. Easy installation into a bucket lid and provides a good sealing. Specification: Colour:black Material:rubber Size:Outer diameter: 1.59cm Package Contents: 150 x Exhaust valve gasket Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.