... joints, reduced rubber joints, rubber elbows, fan coil joint, sewage check valve rubber, rubber filter, rubber compensator ... pipe expansion joints, bellows, waterproof sleeve tube, power delivery Joint, limit expansion joints etc.Registered trademark "Changmao" brand, ... alkali acid concentration, solid-state materials. Material: NO.NAMEMaterial1Inner and outer rubberNR,EPDM,NBR,SI2Key frameNylon Core ...