The Insulated Waterer with Optional Heater has many great features, including: Insulated unit utilizes a 100-watt infrared heater, Auto-fill valve, Water filled with urethane insulation, Made of high-density polyethylene, Removable drain plug for easy cleaning; and made from a single, solid polymer shape, so there’s no chance of electric shock through the water. As well, the heater turns on at 42 degrees/ off at 52 degrees. It measures 22 x 10 x 48 inches; 5-gallon tank handles up to 6 horses.