The Blizz Honey Onyx Vessel Sink will add a touch of nature to your bathroom project. It is made from one solid piece of onyx. It has a polished interior and exterior. Each sink is unique and considered an individual work of art. Please note that there may be variation in stone color and veining. -The drain hole diameter is 1.75 inches. -A 1 5/8 in. Non-Overflow bathroom sink drain is required. -No mounting ring required. -Faucet not included.