Require rubber adapters for plastic pipes. Material is common rubber. Sizes of pipes 20/40, 20/50, 32/40, 32/50, 40/70, 50/70 95/110, 110/120.

Must have not
1. Burr more than 1 mm
2. Excessive elasticity
3. Underelasticity
4. Improper vulcanization
5. Foreign inclusions