Roofjack Silicone Roof Pipe Boots are manufactured from silicone rubber, compounded for maximum ozone, UV light, and temperature resistance. The flexible aluminum base allows the roof pipe flashing to conform to any metal roof configuration. Retrofit roof vent boots wrap around the pipe instead of the standard application of pulling down over the pipe. Pipe sizes are measured by outside diameter. Silicone allows for temperature resistance up to 500 degrees Fahrenheit. Stainless Steel teeth grip the vent boot and secure it tightly. Use urethane sealant and self-drilling screws to complete the installation.