ESR958 is a modern high quality regulator/rectifier that is a Plug-in replacement for the unreliable OEM regulator on various Polaris models. We incorporated our high power single phase rectifier circuit and added the latest generation of our voltage regulation circuit. Our ESR958 offers a rock steady output voltage which means your battery will receive the exact charge rate it needs at either low or high RPMs. Heatsinking is accomplished through the central aluminum heat sink. The rectifier bridge inside our ESR958 is highly efficient and will generate less heat than the OEM unit. However as with all Polaris models we recommend paying extra attention to mounting the regulator on a clean surface and bolt it down tightly. This will ensure a good thermal contact between regulator and chassis which is needed for heat transfer. Our ESR958 is a highly reliable regulator/rectifier that is superior to the OEM unit and comes with a full one year warranty.