QO Load Centers offer premium features like QO breakers, ground arc fault interrupters and surge arresters. QO load centers enable the use of a full complement of accessories. Systems are single or three phase and have indoor and outdoor versions. Indoor enclosures are designed to rotate 180 degrees to accommodate top or bottom service entrance feed which saves expensive service cable. QO load centers feature plated copper bus, providing superior performance and durability. This combination mounting load center cover is painted gray. This cover is for an indoor load center rated NEMA 1 with 42 spaces. This unit is used with Qwik-grip.