Flame retardant thermoplastic. Two side cable knockouts and one 25mm base knockout. This circular dry lining box is easy to work with, featuring two 20mm knockouts and adjustable lugs for simple installation. The lugs have large bearing faces for superior strength and, combined with a flame-retardant thermoplastic construction, make this a tough and durable plasterboard back box. Suitable for fitting board thicknesses from 6.35mm to 15mm. It has an internal depth of 35mm and a diameter of 80mm with a 63mm cutout diameter. The tough yellow nylon lugs have large bearing faces for superior strength. The large flange around the front matches the profile of accessory front plates and prevents slipping into the cavity. It has a 25mm base knockout plus 2 side cable entry points.