SpaGuts 25-200-0100 Universal Flo-Thru Heater Element, 5.5 KW, Non-Coated Incoloy Made of Incoloy, the standard type heater element primarily used in most spa controllers in the after-market and OEM controller or packs. Heater Elements are OEM Factory Replacement Parts assembled in the U.S.A. Listed for your safety at the USA and Canada Underwriters Lab. Approx. Dimension: 10-inch L x 1.37-inch W, normally used in a 15-inch long Flo-Thru heater metal tube that is at least 2.25-inch in diameter (also known as 2-inch heaters). Distance between the heater terminals from the center point is 1.25 inches. The heater terminals are more towards one side of the heater. Note: For 110V application, the 5.5 kw heater element outputs 1.375 kw (5.5 kw = 18766 BTU). This replacement heater element fits any spa packs controllers that takes a universal hi-flo element, including products made by Balboa, Gecko, Spa Builders, Hydro Quip, ACC, Acura Spas, Len Gorden, Coleman, Watkins, Dimension One, etc. This is also an optional replacement for these heaters: C2550-0304A, C2550-1056, C2550-1054, 2550-0535, C2550-0809, C2550-0807, C2400-0807, C2550-0066ET-A, C2550-0321-A, C2550-0621, C2550-0621-A, C2550-0165, 20-00517, C2550-2315, C2550-0155, C2550-0309, C2550-0307, C2550-0736, C2550-0071, C2550-0073, C2550-0313N, C2550-0213N, C2550-0256, C2550-0056, C2550-0120, C2550-1227, 25-250-1012, 25-150-1020, 25-150-1040, 48-87B-S00-1PP3, C2550-5000-2, C2550-1322, 58083, 25-175-1010, 58010, 58121, 58209, 58000, 58123, 58089, 58086, 58105, C2550-0807-TPS, 25-250-0807, 58015, 58274, 58272, 20-00232, C2550-0304, C2550-0801A, 46-371-1208, C2550-0601ET, C2550-0802ET, C2550-0800, C2550-0800ET, C2550-0800ET-G, B24055GM, 20-00272, 20-00274, 530AA0107, C2550-0601, C2550-0802, C2550-0800, 25-250-1000, 25-250-1003, C2550-1206 (13in), C2550-C3330-1 or C2550-C3330-1A (Caldera Spas), 58140, C2550-5000-2, C2550-5000-2B, C2550-0456, 58140, C2550-5000-1.