TRUaire's Stamped Steel Supply Registers are made of quality steel, and feature our exclusive SmoothGlide Technology, which powder coats every piece, prior to assembly, something no other register and grille manufacturer offers in the industry. TRUaire offers two series model types; 100 are the standard, 400 have stamped curved blades. Both models feature countersunk screw holes, a pristine white powder coat finish, and the economical price that comes with using steel. Our curved blade Steel Supply Registers (400) simply provides a classier look, and a more even air pattern. The choice is yours to make.