Black outer / white inner bulb holder can be used on top of Vivariums which have mesh tops to provide a heat source. This unit has a ceramic holder for use with screw type bulbs (E27 – 1″ diameter thread) up to 150W. The cable has a switch, and it is also supplied with a clamp which allows the holder to be fixed to the top of the cage, etc. For use in brooders, Vivariums, planters, etc. The top of the holder also has a hook. Size : 220mm (9″) diameter; 180mm (7″) Height.