Designed to connect a water closet outlet to a plumbing system and sit flush with the floor. Oatey 3" or 4" Level Fit Long Pattern Closet Flanges solvent welds over 3" Sch. 40 DWV pipe or inside 4" Sch. 40 DWV pipe. IAPMO. Extra thick flange with four mounting slots. Countersunk screw holes provide secure attachment to floor. Flange sits flush on floor.