Flexible joint (bellows) is used to reduce vibration in the exhaust system of vehicle. Also, bellows eliminates damage of tubes resulting from vibration. There are three types of bellows: a three-layer, reinforced and VW-type. Bellows consists of a base (corrugated tube), external and internal braid and flanges.
The base of bellows consists of double stainless steel layer. Its weave is made of stainless steel, and flanges are of aluminized steel.
There is also a type of reinforced bellows with inside braid in the form of a lock. It is much tighter and more heavy-duty version of bellows. Like a three-layer bellows, it consists of a base (corrugated tube), external and internal braid in the form of rolled lock and flanges.
VW-type bellows is similar to reinforced bellows, but with a unique distinction. For a more durable service, aluminized corrugated flanges are replaced with stainless steel rings.