The Contractor Series RT4 and RT5/6 is a 4 in., 5 in. and 6 in. compatible LED recessed downlight kit creating high performing white light and is optimized for new construction and retrofit applications. Installation is done quickly and easily in most standard 4 in., 5 in. or 6 in. Insulated Ceiling (IC) housings, Airtight (AT) housings and non-IC housings. Dimming The Contractor Series LED RT4 and RT5/6 recessed downlight kits are dimmable down to 25% of full light output with compatible dimmers. The minimum dimming value is based on light output using compatible dimmers and may not be an indication of the kit's full rated capability.