#MT0500IN09C1PNJX Pentair Commercial Megatherm 500 BTU Cupro-Nickel Indoor High Performance Electronic Ignition Pool Heater, with CSD-1Natural Gas500 BTU Cupro-Nickel Heat Exchanger MegaTherm High Performance Electronic Ignition Heaters...Powerful, efficient, and reliable, MegaTherm pool heaters are designed for commercial, institutional and large residential pools where economical performance and rapid heat-up are required. Available in indoor and outdoor models in both natural and propane. MegaTherm is design certified to the ANSI Z21.56 Standard for Gas-Fired Pool Heaters. (Outdoor 500-1825 units are certified for use without the addition of a draft diverter or external vent. Indoor units incorporate a built-in draft diverter and require only vent piping.) Salt water models (500-1825) are available with cupro-nickel alloy heat exchanger tubes and bronze headers and header covers.Features:Electronic ignitionBuilt-in draft diverter (indoor models) simplifies installationIntegral pump assures proper water flow (Models 500-1825)Automatic gas valveStainless steel burners, with slide-out burner tray for easy maintenance and long life (Models 500-1825)High temperature refractory firebox liner to 2000° F for greater efficiencyEasy-to-service header flangesCorrosion-resistant glass-lined or bronze headersCSD-1 and other options available. Contact factory for part numbershttps://www.pentair.com/en-us/products/business-industry/commercial-pool-products/commercial-pool-heaters/-megatherm--high-performance-electronic-ignition-heaters.html