This pump rotor ring fits many heaters from 30,000 BTU thru 200,000 BTU that use a 1/2 inch thick rotor. Make sure you measure your rotor before ordering. The 1/2 inch thick rotor is the most popular, but alot of heaters also have the 5/8 inch thick rotor and if you have an older unit it can also be 3/4 inch thick.