Product Information: Pentair SR400HD StaRite MaxETherm InGround Low NOx Pool amp; Spa Heater Heavy Duty 400K BTU The Pentair MaxETherm Pool amp; Spa Heater Series is an economical choice to bring reliability and performance into heating your pool or spa. MaxETherm heaters are compact, leaving more room on your equipment pad for other equipment. MaxETherm heaters will heat your pool quicker due to its unique fueling and ignition process. The DuraGlass construction is anticorrosive for many years of quality operation without the concern of weather conditions, or rust (great for humid or wet areas). MaxETherm heaters are Low NOx heaters which meet regulations where low emission heaters are required. The low emission heaters are better for the environment, and operate at a more efficient rate than previous heater models. Upgrade today, go green, and increase your pool or spa efficiency. Specifications: Gas Type: Natural Gas Dimensions: 25.15" W x 31.69"D x30.03" H Venting: Top Vent BTU Input: 400,000 Ignition: Hot Surface Technology Thermostats: 1 6" clearance required on all sides for proper operation Additional Information: Features: Low NOx Emmissions (EcoFriendly) Super Quet Operation allows you to enjoy your pool time more comfortably RustProof Exterior to weather the elements High Efficiency Rating Special Designed System Heats Your Pool / Spa Faster Easy to Program Control Panel Offers Best InClass Efficiency Specifications: Gas Type: Natural Gas Dimensions: 25.15" W x 31.69"D x30.03" H Venting: Top Vent BTU Input: 400,000 Ignition: Hot Surface Technology Thermostats: 1 6" clearance required on all sides for proper operation