Laboratory sinks are designed for lab or clinical environments where potentially corrosive materials need to be disposed down a drain. These sinks are fabricated from HDPE or stainless steel to withstand corrosion or chemical reactions. Counter-mounted sink models are typically a "drop-in" design that have a rolled or molded rim or protruding edge to sit on the countertop and overhang the hole in the countertop where the sink will remain. Cup Sinks are round, deep bowls especially designed to improve drainage and protect against splashing.