1-7/16 in diameter faucet punching, 4 in centers on 3 main holes, 4-13/16 in center to sink edge for 4th hole. 3-5/8 in diameter centered drain hole for 1-1/2 in centered outlet each basin. Made from single sheet of high-grade stainless steel with continuous weld stainless steel channels for a smooth, attractive surface. SilentShield sound-deadened bowls with asphalt-petroleum-based full coverage undercoating to reduce noise and vibration, and to prevent condensation. Rolled outer rim and pre-assembled clips for easy installation. Includes installation hardware. Requires 32-1/2 in x 21-1/2 in cutout with 1/2 in radius corners and offers two 14 in x 15-1/8 in x 8 -inch D basins.