Description: and . Made of EPDM rubber, has good aging resistance. quiet and long service life. Suitable for aquarium air oxygen pump. 4 Size can be choosed. Specification: Material: Plastic Size 1: Inner diameter:1.8cm or 0.71 inch,Outside diameter:2.5cm or 0.98inch,Height:1.5cm or 0.59 inch,Top Small circle diameter:Approx.0.7cm or 0.28inch Size 2: Inner diameter:2cm or 0.79 inch,Outside diameter:3.3cm or 1.3inch,Height:1.5cm or 0.59 inch,Top Small circle diameter:Approx.0.7cm or 0.28inch Size 3: Inner diameter:2.1cm or 0.83 inch,Outside diameter:2.8cm or 1.1inch,Height:1.5cm or 0.59 inch,Top Small circle diameter:Approx.1cm or 0.39inch Size 4: Inner diameter:2.5cm or 0.98 inch,Outside diameter:3.1cm or 1.22inch,Height:1.5cm or 0.59 inch,Top Small circle diameter:Approx.1.1cm or 0.43inch Package Includes: 10 Pieces Air Pump Rubber Accessories Note: 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. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.