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. Designed with 2" offset to allow for a margin od error for drain pipe / flange allignment. Designed with 2" offset to allow for a margin od error for drain pipe / flange allignment.