Creative Engineers [M] manufactures Straight through Series Coupling. Creative Engineers [M] also manufactures various types of Pneumatic, Hydraulic and Special-purpose couplings under the brand name Rapilink which are used in flow lines for transferring variety of fluids at different temperatures and pressures. The Straight through Series Coupling is used in pneumatic applications. The Straight through Series Coupling has no check valve. The Straight through Series Coupling is available in various sizes and is available in seals made of Nitrile and Fluorocarbon.