Imperial 4 in. D 30 Ga. Galvanized Steel Round Starting Collar, Pack of 6

This Imperial Round Collar provides a reliable transition from a rectangular duct or a plenum to round pipe or insulated flexible duct. It features a crimped end for easy installation and attaches to a flat surface with tabs that create a tight lock. Built to last, the round starting collar is made from 30-gauge galvanized steel for rust resistance and durability. It is suitable for use in most heating, venting and air conditioning applications.