Designed specifically to eliminate toxic gases from fish ponds without high energy costs and consumption- doesn't waste energy heating to maintain a large hole in the ice. Protects at ice depths up to 15". Designed to freeze into the ice and move water above the ice layer for gas exchange: exposes more than 4,000 times the water surface. Creates a gentle current to move oxygen throughout the pond and adds only enough heat to keep the water flow open. Operates at an energy efficient 40 watts.