Profile: Triad Bellows Design and Manufacturing, Inc. offers custom metal bellows and expansion joints. We specializes in the design and manufacturing of metal bellows expansion joints specifically engineered for the engine exhaust industry. The minimum pressure rating on exhaust expansion joints is 5 PSIG @ 1000?F making them the perfect solution for blower, fan, and other low pressure piping applications. Single-ply and multi-ply expansion joints for diesel driven generators, marine exhaust and numerous other hot air piping systems.