The Ceiling Collar has a slightly oversized opening to accommodate pipe. This collar is designed for use as a finishing piece to help hide surface imperfections where pipe passes through a ceiling, wall or floor. It is made of 30-gauge, galvanized steel to provide strength and durability. Made of 30-gauge, galvanized steel for strength and durabilityDesigned for use as a finishing piece to cover imperfections where pipe passes through a ceiling, wall or floorA slightly oversized opening to accommodate 4 in. pipe