GE's Fluorescent Starters provide a high-quality replacement option for fluorescent fixtures. Use these FS-25 automatic starters with 24-inch, 28-inch, 30-inch and 36-inch T8 (1-inch diameter) and T12 (1-1/2-inch diameter) fluorescent light bulbs. They also work with 6-inch diameter and 8-inch diameter circline fluorescent light bulbs. Works with 18-Watt, 20-Watt, 22-Watt and 25-Watt T8 (1-inch diameter) and T12 (1-1/2-inch diameter) fluorescent light bulbs