Not to get too technical on you, but top-mounted sinks (also known as over-mounted, self-rimming or drop-in) are mounted on top of a counter-top. (Makes you think, doesn't it?) Top-mounted sinks have a lip that sits on the surface of the counter-top. In most cases, they are held in place by clips and screws. Although top-mounted sinks are easier and faster to install than under-mounted sinks, the raised lip that rests on the counter surface can make clean-up a little more difficult. Top-mounted sinks are commonly installed in laminate counter-tops. Know why? Because the lip covers up the seam where two parts of the laminate come together. Here's another piece of kitchen sink trivia: Most stainless-steel sinks are top-mounted.