Quality materials: Our airlock grommet is made of durable silicone and BPA-free materials, resistant to high temperatures for long-term use Good performance: This fermenter lid grommet is easy to install into the lid and provides a hermetic seal to protect food from oxygen; Use with airlocks to extend fermentation time Hermetic sealing: This silicone grommet works well with airlocks to create an effective seal, preventing oxygen from entering the fermenter and supporting consistent fermentation Quantity and size: You will receive 50 airlock grommets with an outer diameter of 5/8 inches and an inner diameter of 3/8 inches; Drill a 5/8 inch hole in the fermenter lid for easy insertion Wide use: This airlock gasket is compatible with most airlocks, plastic lids, and straws; Use these silicone gaskets to convert mason jars into fermentation vessels Features: Made of durable, long-lasting silicone, the airlock grommet offers reliable sealing performance and fits most standard airlocks Various applications: This grommet is compatible with a wide range of airlocks, bucket lids, and straws, making it easy to create custom airlock lids for fermentation; Simple to install and provides a secure seal Specification: Color: Black Material: Silicone Size: Outer diameter: 1.59 cm Package Contents: 50 x Airlock grommets Note: Light and display differences may cause slight color variations. Measurement error allowed is +/- 1-3 cm