These 4-pin pin-based SpringLamp bulbs fit in TCX style adapters, which are used in some TCP light fixtures and two-part screwbase lamps. All lamps are rated to last for 10,000 hours and have a "warm white" (27K) color temperature, except for the 20 watt, that is also available in a cool white 4,100 degree Kelvin color temperature. * Dimensions (15w): 2.2" wide x 3.15" long * Dimensions (18w): 2.2" wide x 3.45" long * Dimensions (20w): 2.2" wide x 3.45" long * Dimensions (23w): 2.2" wide x 3.70" long * Dimensions (26w): 2.2" wide x 4.35" long * Dimensions (32w): 2.2" wide x 4.80" long * Dimensions (42w): 2.2" wide x 5.00" long * Light Output (15w): 930 lumens * Light Output (18w): 1,100 lumens * Light Output (20w): 1,200 lumens * Light Output (23w): 1,400 lumens * Light Output (26w): 1,750 lumens * Light Output (32w): 2,100 lumens * Light Output (42w): 2,800 lumens * Color Temperature: 2,700 degrees Kelvin * Color Rendering Index: 84 CRI