SpaGuts Balboa brand OEM VS M7 Heater Assembly with Dual Sensors. This is the "Original" heater by Balboa. OEM part number 58083. Heater Dimensions are approximately 15" L x 2" Diameter (Actual hole diameter is 2. 25"). Note that the Heater Split Nuts have an inside nut diameter of approximately 3. 1". This heater is also a replacement option for the following heater part numbers: 26-58083-7S-KS, 26-0807-7S-KS, 2-00-0036C, C2550-0807-TPS, 58121 (1. 5" Tailpiece), 58209, 58000, 58010 (825 Incoloy), 58123, 58089 (Incoloy), 58086, 58105, 46-138-1020, 58016, 55473, 58140, 740-0617, 740-0655, 2-00-0049, 58306 (has BP Heater Cable), 55624 (Has Titanium Element), Master Spas X300713, 58016 (Marquis Spas), 25-250-0807, 25-200-8083. This item carries a 1-year limited .