This round bar/kitchen copper sink has a standard 3.75 diameter hole at the bottom center, it fits the 3.5" diameter drainage size. The copper sheet is 16 gauge (0.05" thickness). The finish is in terra, which is composed mostly of light brown shades. If scratched, it will heal by itself, if it does not, we have a way to re-apply the patina it back!From a copper sheet the wise artisan hands transform it into this unique piece. It is designed to be either dropped-in or under-mounted because the rim is flat.IMPORTANT NOTE: The patina can be damaged faster if abrasive substances are used to clean it, because of this, we recommend rinse it with water and soap only!"Hand-hammered and mold-cut to perfectionHandcrafted by Mexico''s Finest ArtisansWe include 1" long brown screws in all of our hammered copper switch plates