With undermount sinks, the sink is positioned directly below the worktop. The natural stone surface continues beyond the edge of the sink. As a result, there are no differences in height or gaps in the surface and the worktop is easy to clean around the sink. The edge of the sink cutout is always matt ground. Undermount sinks can be provided with optional draining board or draining grooves. These are produced with a slight gradient towards the sink so that water can drain away unimpeded.