NBE compression couplers use a wrap-around compression design to enable secure assembly of dry bulk material transfer systems. Constructed of zinc-plated steel, the NBE compression coupler with black gasket is an excellent method for joining pneumatic dry bulk material handling equipment. National Bulk Equipment compression fittings are available in lengths from 4 to 8 inches, and O.D.s from 1.5 to 6.625 inches.