CNZ airline suction cup is made of soft plastic material, 100% safe to fish. it will stay firmly on the surface of your fish tank or aquarium. Fit for 3/16" ID or 1/4" ID airline tubing.

• Fit Airline Diameter : 0.5 cm/ 0.2";Suction Cup Diameter : 2.5 cm/ 1"
• Material: Plastic; Color: Clear, White
• Each suction come with one clip
• Fit for standard size airline tubing or CO2 tubing

Fit Airline Diameter : 0.5 cm/ 0.2";Suction Cup Diameter : 2.5 cm/ 1"CNZ