These nets normally are a 4-panel construction. They are intended for fishing above all demersal species and pelagic species behaving like demersal ones, at least at certain times of year or given moments in a day. The net's size and specifications vary according to the target species, working depth, boat horsepower,... Hence, there exists a fairly large group of trawls to choose from, which share only a couple of features, namely the construction that normally exceeds 2 panels and their operation on the seabed.