Hi. The gauge is 18 which is standard for an under mount installation sink. Even though the gauge is important what gives the piece its strength is the hammering and heat treat process. There is no overflow on the sink so you need to use a non-overflow drain. A Pop Up drain for non overflow sinks will work. We sell a few drains that cosmetically match and work with our sinks. Please visit our Drains Collection in Houzz under Artesano Copper Sinks. Best.