Westbrass 1-1/2 in. NPSM coarse thread Integrated overflow bath drain with Tip-Toe mushroom drain closure. European style round full cover mushroom cap Push down cap to close and restrict draining water, push again to open the drain. ADA approved. For use in bath tubs with integrated overflow channels cast into the tub shell during the bath tub manufacturing process. Heavy duty metal construction with adjustable plastic tip toe cartridge. Do not use plumber''s putty for installation, use silicone seal.