Two piece moulded nylon construction.Press Collar onto Drain Socket for easy installation.Sealant recommended for water tight seal.Other Details: Part No. Description FlangeO.D. (mm) I.D.(mm) Max. HullThickness (mm) Cut OutØ (mm) 29775 Splash Well Drain with Push-On Collar 31 18 75 25 29780 Splash Well Drain with Push-On Collar 32 19 52 25