Gas delivery tubes made of Soda glass.Outer Diameter: 6mmInternal Diameter: 4mmThis set comprises of:-1 x short, straight: 70mm length1 x long, straight: 170mm length1 x 90° bend, arms: 60mm,160mm length1 x 90° bend, arms: 60mm longIt is not recommended that these tubes be exposed to temperatures above 60°C.