The UniRac No-Calk Collared Flashing is designed to prevent water leakage around a UniRac standoff. Unirac 990103 No-Caulk Aluminum 18" x 18" Flashing 12pc, All Metal Packages each include 12 flashings. Fits standoff O.D. of 1 5/8 inches. Oatey # O-12836. Not for hot mopped or built-up roofs. Soft Aluminum flashings can be molded to fit curved roofing material, such as Spanish tile. These flashings work with steel and aluminum standoffs.