Jones Stephens has built its reputation over the years as a leader in the plumbing industry, providing the market with thousands of products to complete any project. All parts are designed with quality engineering and construction to be durable and reliable and to meet Jones Stephens highest quality standards. Schedule 40 DWV pipe. It comes complete with 6 screw holes and radial slots for closet bolts. The 400 grade stainless steel ring is constructed to the highest industry standards for durability and longevity, and the knockout is ready for testing. It's easy to remove and comes out in one piece.