Oatey 1.25" – 1.5" Galvanized 18" x 18" base Oatey Galvanized No-Calk Roof Flashings are designed for commercial and residential applications that require a watertight seal for roof penetrations around the plumbing vent pipe. Self-sealing collar slides over pipe and requires no caulking. Oatey products have earned the trust of plumbing professionals for over 100 years.