Description: - and high quality. - Made of EPDM rubber, has resistance. - quiet and long service life. - Suitable for aquarium air pump. - Aquarium air pump accessory.Specification: - Material: Plastic - Size 1: Inner diameter:2.1cm/0.83 inch,Outside diameter:2.8cm/1.1inch,Height:1.5cm/0.59 inch,Top diameter:Approx.1cm/0.39inch - Size 2: Inner diameter:2.5cm/ inch,Outside diameter:3.1cm/1.22inch,Height:1.5cm/0.59 inch,Top diameter:Approx.1.1cm/0.43inchPackage Includes:20 Pieces Air PumpNote:Since the size above is measured by hand, the size of the actual item could be slightly different from the size above.Due to the lighting effects, monitor settings, etc. There could be some slight difference in the color of the pictures and the actual item.