Elegant Hardware 12 by 12 by 5 inch square undermount copper bar sink adds elegance to any room. It features 17 gauge copper and we guarantee the weight (sink only – not shipping weight) to be at least 2 LB 7 OZ. The hole for the drain is flat edged, not punched into a cone, which ensures a solid seal for 3.5 inch drains – perfect size for a garbage disposal or drain. The Sierra Fired Copper finish affects the copper itself – much more durable than a finish created with acid or paint; each sinkâs finish is similar but unique. The forming by tight hammer strokes adds additional strength and beauty to copper .