Nantucket Sinks UM-16CW undermount sink has graceful lines and a flatter bottom give it visual interest and stand out as a design feature. Made of vitreous china, this bathroom sink is unique; while it is technically an oval, it comes close to being a circle. Features a center drain and overflow. Beautiful round shape in a classic white glazed finish. Porcelin glaze makes for easy cleaning. Top edge and bottom are unfinished as it is designed to be undermounted. This sink has a 1.75" drain opening diameter. Drain is not included with sink. Nominal dimensions due to firing process.