Reviews Description: 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 200W. 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 holder can be suspended using a handle mounted in the top. Size : 270mm (10½") diameter; 210mm (8") Height.