Simply Conserve G24Q/GX24Q Vertical PL 18-Watt EQ Single tube Daylight Gx24q-4 Pin Base LED Light Bulb (4-Pack) in the General Purpose Light Bulbs department at Lowes.com
LED PL Retrofit Lamp for 2 or 4 Pin CFL Bulbs - Replaces 13-18 Watt- G24d / GX24d & G24q / GX24q Base Lamps - Magnetic Ballast Compatible or Bypass, 4000K and 560 Lumens
Feit Electric 13-Watt Equivalent PL CFLNI Quad Tube 4-Pin G24Q-1 Base Compact Fluorescent CFL Light Bulb, Cool White 4100K (1-Bulb) BPPLD13E/41/HDRP - The Home Depot
LED 4-Pin PL Lamp – Forthright LED Lighting
2G7 LED PL Retrofit Lamp for 4 Pin CFL Bulbs - Replaces 7-9 Watt- 2G7 Base