Semi-countertop basins (also known as semi-recessed) sit half in & half out of a countertop or worktop and are usually used with fitted furniture. The basin will be in contact with the worktop over a larger area and the tap may be fixed onto the basin or, like the vessel basin, can be mounted next to the basin on the countertop or on the wall behind (a no tap hole basin would be required which is more rare).
Both the worktop and the basin furniture top fascia will require cutting but a template is normally supplied with each basin. The ceramic is slightly larger than the cut out so that the overhang will cover any cuts giving a neat finish.
Some ranges have a slim or standard depth size to fit different furniture depths. The slim depth basins sometimes have the tap in the corner to give a more usable bowl size. Available in 0, 1, 2 or 3 tap hole