3.5 Inch Low Voltage MR16 Airtight IC New Construction housing for areas with insulation. Insulation should be 3 inch minimum away from housing. Includes magnetic transformer with internal thermal protection. Adjustable mounting bars 10 to 24 inches. Requires one 50 watt maximum 12 volt GU5.3 MR16 halogen lamp, not included. Can also be used with one 5 watt 12 volt GU5.3 MR16 LED lamp, not included. .cUL listed. For use with trims X3501, X3502, X3503, X3504, X3505, X3507 and X3508. Dimensions: 14.5 inch length x 13.4 inch width x 7.5 inch height. 3.622 inch ceiling cut out.