These electronic regulators replace the end bell and become a structural part of the generator. The current limiting circuit senses armature temperature and adjusts available output to allow for maximum amperes without overheating the armature. This gives you more power for faster battery recharging and cooler operation for longer generator life. Can also be used without battery. Will not fit some models with foot clutch. Installation on FL models with an OEM pre-1992 or aftermarket generator with the fins level with the motor requires the separate purchase of the ZPN 782246 end plate.