(Pack of 4) 13 Watt Single Tube 2 Pin GX23 Base - 5000K Bright White 50K - CFL Light Bulb - Replacement for Sylvania 21135 CF13DS/850- Philips 146878 PL-S 13W/850 and GE 97572 F13BX/850Color:5000K (Bright White) (Pack of 4) 13 Watt Single Tube - Gx23 (2 Pin) Base - 5000K BrightWhite - CFL Light Bulb. GX23 Base: Plug-in CFL sockets are designed to only work with one style of pin base to ensure the correct light bulb is used to match the ballast in the fixture. So make sure that the base (Gx23) matches exactly to your fixture socket as this will only work with this specific base number and will not interchange with other base/socket numbers Energy Saving: Save 70% on your monthly electric bills with these 13W Compact Fluorescent Gx23 bulbs that are as bright as the traditional 60W incandescent bulbs but consumes less energy. Color Temperature 5000K: This 50K color (Bright white) temprature is more neutral and gives out a cool clean look and works well for task lighting in kitchens, bathrooms. It is perfect throughout your home and can be used in your desk/table lamps, floor lamps, and open pendant fixtures. Long Life: This 13W compact fluorescent bulb offers a long life compared to a regular 60-Watt incandescent bulb which makes it a maintenance free option to light your house or any lighting application. Dimension: Overall length 7” These 2-pin CFL bulbs are designed to be an exact replacement for major brand bulbs like Sylvania, GE, Philips etc. They are made with great care and quality at a fraction of the cost of the major brands while not compromising the quality or the lifespan of the bulbs.