This 3 Way 12/20/26 watt compact fluorescent light bulb has a color temperature of 2700K and a Color Rendering Index (CRI) of 82. The warm yellowish glow of an incandescent light that you are used to is about 2700-3000 Kelvin (K) . The Satco S7341 mini spiral (also called a twist or twisty bulb or curly bulb) cfl light bulb fits all fixtures. They are just 2.36 inches wide and 6.02 inches MOL . They incorporate an electronic ballast for Instant On, flicker free operation. These ENERGY STAR Qualified fluorescent bulbs replace your incandescent 30/70/100 3-Way and consume only 12/20/26 watts of energy. These eco friendly cfl bulbs are rated for 10,000 hours and carry a (2) year limited warranty. The minimum starting temperature is 0 degrees fahrenheit and the maximum operating temperature is 100 degrees fahrenheit. These 3 Way CFL bulbs are NOT for use in totally enclosed fixtures and are NOT for use on circuits with dimmers, timers or other control devices.