Legrand Three and Four Compartment Cavity Box Base and Accessories 3 and 4 Compartment floor box bases, manufactured in pre-galvanised steel and polycarbonate/ABS. The floor box base is supplied empty and with no lead, wiring accessories and leads can be bought separately. Supplied empty Recommended hole cut-out size : 340-342 mm x 203-205 mm Note Cavity box base is not supplied with lid