CalExotics universal silicone pump sleeve Fits Up to 3″ / 7.5cm Diameter Pump, a replacement seal/sleeve that fits most penis pumps. The seal is the part that goes into the chamber and round your dick, keeping the air in and creating a vacuum. The better the seal better your cock and the penis pump the better the results. As a universal replacement seal this fits most penis pumps up to three inches wide. Made from pure silicone the seal/sleeve is not suitable for use with silicone lube.