Danner PondMaster 20W UV Clarifier Supreme # 12972, 02920 20 Watt UV Bulb, Model: 12972-1, Home & Garden Store Effective Hours Rating: 12,000hrs - Ultraviolet Germicidal Light Bulb Includes Free Gloves for Handling Length: approx: 14.5 Bulb Type: T5 Style Quartz Glass SPLIT BASE ON BOTTOM OF THE BULB -EXACT PART