Master Flow™ Versa Cap Adjustable Pipe Cap helps protect rooftop flues, hot stacks, and B-vents. The adjustable design offers convenient installation with a screwdriver-adjustable clamp to ensure a tight fit. Aluminum construction helps resist rust that can detract from the look of your roof and provides a neat, finished appearance. Positive draft design helps reduce the risk of clogging. A large selection of sizes is available to fit pipes with outside diameters ranging from 2 7 ∕8" up to 10 7 ∕8"