Juno Lighting T812BL Trac-Master Duo Open Back Low Voltage MR16 Lampholder, Black,Juno Lighting Group,T812BL" /> Height: 5-5/8-Inch, Width: 8-1/4-Inch Ceramic sockets use two 12V, 20-75W MR16 bi-pin lamps Copper alloy contacts provide precise spring action - no arcing, will not take a set and pulls to up position for two-circuit application Extruded aluminum vertical black monolith holds durable die-cast aluminum concentric gimbal rings that offer optimum adjustability Dimmable using dimmer specifically designed for use with electronic transformers