From the inside out, the MiniMax® CH heater is designed for easy and reliable use. It features high efficiency, faster heat-up times and lower operating costs. Plus, its space saving, low profile design blends easily into the backyard decor. Composite Header Precision Dual Electronic Thermostat Easy-to-Install CPVC bulkhead connections and reversible headers allowing direct PVC connections Standard balanced flue stackless top for outdoor installation Designed for high efficiency For indoor installation, see Indoor and Outdoor Vent Kits Low profile design with rounded corners The MiniMax® CH Heater uses a flow valve that incorporates a molded plastic design and improves performance.