The TRUFAST Aluminum Retrofit Roof Drain with sealant tape features a 2ʺ (51 mm)-wide band of high density, expanding foam tape impregnated with asphalt that is factory applied in a compressed state around the drain outlet. Sealant tape is designed to expand to approximately four times its compressed thickness. Just prior to inserting the drain, the installer removes the exterior compression tapeadn immediately sets the retrofit drain in place. The released tape gradually expands to fill the space between the TRUFAST drain and the existing drain sleeve, making the connection watertight. TRUFAST sealant tape expands more slowly in cold temperatures. When heat is applied to the inside of the outlet, the sealant tape expands more rapidly. Should the tape excpand too much before inserting the TRUFAST drain, simpley recompress the tape by hand and then insert the drain.