Replace an ordinary screw fitting light bulb with this energy saving black light blue ultraviolet UV helix spiral light bulb and you can instantly flood a room with ultraviolet light. Features a ES-E27 Edison screw (27mm) base/cap. One 25W light bulb is enough to create glow in the dark lighting effects in a medium-sized domestic room making these ideal for parties, discos, pubs and nightclubs as well as for a range of industrial uses. The triple turn compact fluorescent design makes this both efficient and extremely compact. Not suitable for dimming.