Flight Systems part number Model 305 is an improved, direct replacement for the voltage regulator used in several models of Onan Emerald, Marquis, and Microlite Series Gen Sets. Features include improved circuit design, rugged weather-proof packaging and better heat dissipation (through gel encapsulation and larger internal heat sink). Unlike the epoxy encased originals, the Model 305 can be rebuilt. It is built in the USA and backed by a 2-year Warranty. This regulator replaces the following ONAN part numbers: 305-0809-01, 305-0851, 305-0782-01, 305-0830-01, 305-0826