This 3/4HP De-icer Replacement Propeller is compatible with the following De-icer part numbers: 3400D025, 3400D050, 3400D100, 3400D150, 3400D200, 3400HD025, 3400HD050, 3400HD100, 3400HD150, 3400HD200, 3400HD250, 3400HD300, 3400HD400, and 3400HD500. Use this prop to replace your old or broken De-icer propeller to keep your unit operating at its best. Kasco De-icers are designed to create an ice-free area at the waters surface by pulling warmer water up. This protects boats, dock, and other in-water structures from damaging ice build-up and keeps fish and other aquatic species healthy throughout the winter by allowing for open areas where oxygen can enter the water.