Automobile exhaust flexible sylphon bellows (HYQ Type) Structure: double layers with out braid/may add interlock Features: used for automobile exhaust system, installed between engine and muffler, decreasing engine noise and vibration, it's durable has long useful time, expands with heat and contract with cold, preventing steel breach. Inner Diameter: Φ25(1")-Φ150(6") Length: Φ102(4")-Φ355(14") Use : used to decrees absorption of vibration for Automobile exhaust pipe