NPT PC: 2" X 4"DRUFH 2" x 4" Diana Royal Marble Split Face Coping. Whether creating a patio, a walkway, or a pool deck, NPT natural stone hardscapes are the perfect fit for your pool area. Coping provides a smooth surface and acts as a great finishing accent for any pool. It covers your pool's concrete edges and prevents water from getting behind the pool shell and walls. A coping finish is perfect for outdoor pools, creating a softer look and feel around your pool!