Ace Race Parts 79008 4.000 ID Flex Bellow x 5.236 Overall Length - CP2 TitaniumAce Race Parts 79008 4. 000" ID Flex Bellow x 5. 236" Overall Length CP2 Titanium ULTRA LIGHTWEIGHT, SINGLE PLY TITANIUM FLEX BELLOW The Ace Race Parts brand of CP2 Titanium Flex Bellows is designed to accommodate thermal expansion in high performance automotive applications, such as exhaust systems. This particular 4. 000" ID Titanium Flex Bellow features a slip fit design, enabling the matching Titanium Tube size material to slip into the bellow