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