URS Lead E27 Ceramic Screw Fitting with in-line switch. These fittings are easy to install in Terrariums and are suitable for all E27 Screw in bulbs available (up to a maximum of 250 Watt), including Ceramic Heat Emitters, UVA Basking Lamps, Infra-red Heat Bulbs and Mercury Vapour Lamps. (Please note: I strongly recommend that Ceramic Heat Emitters are used in conjunction with URS READY WIRED MESH COVER to avoid accidental contact with these bulbs.)