Umbrella lavatory drains open and close by pushing on the mushroom cap. This design seals well and eliminates the pull rod and linkage common in traditional lavatory drains. This drain has overflow drain holes in its drain cup; however, its unique design allows it to be used on sinks without overflow. The drain is fully finished below the sink, and the screw mounting system makes it ideal for extremely thin sinks. European umbrella push-down stopper. Fully finished for exposed installation. Fits extra-thin sheet metal sinks. Fits sinks up to 2-3/4 in. thick with an opening of 1-1/2 - 1-5/8 in. opening. Uses a 1-1/4 in. tailpiece. Heavy brass construction