Keyless Plastic ceiling lamp holders are molded of high-temperature, thermoset plastic to reduce breakage. Mounts on 4 inch (101.6 mm) outlet boxes with breakout for 3-1/4 inch (82.5 5 mm) box mounting. Leads are 6 inch (152.4 mm) 105 degrees C insulated stranded #16, stripped 3/4 inch (19.05 mm).