Profile: Bellows Systems, Inc. designs and manufactures metal bellows, expansion joints, and exhaust systems. Our products are used in diverse industries such as oil & gas transmission, petrochemical plants & refineries, power generation, defense, automotive, and aerospace industries. Single-ply Bellows are made up of a single tube (ply) of sheet metal of a defined thickness. They are typically suitable for applications having relatively small thermal movements and vibrations. Single-ply bellows are specifically designed for low pressure, high spring rate applications (150 PSIG at 1000 deg. F) where the single thin sheet metal is sufficient to withstand the design criteria.