Boxes mount securely to stud. Separates supply and drainage systems into two stud bays. Separate boxes offer flexible layout. Durable ABS stands up to job site abuse. Drain knockout is easy to remove with pliers. With two Mini-Rester water hammer arresters. Debris covers included to protect boxes from drywall mud and paint. High-quality quarter-turn ball valves. ¾" male hose-thread outlet connections.