Raychem H921 WinterGard Junction Box Kit, Knockouts: No, 4-3/4 IN Width, 3-1/2 IN Depth, Height: 4-3/4 IN, Enclosure: Nema 3, UL Listed Standard, For Use Only With The WinterGard H900 Power Connection Kit and H311, H611 or H612 Self-Regulating Heating Cables Application