A UPS (uninterruptible power supply) is a device that provides temporary backup power to electronic devices in the event of a power outage or surge. In the retail industry, it is used to protect point-of-sale systems, servers, and other electronic equipment that is critical to the operation of a store. It allows for a smooth transition to generator power or other backup power sources in case of a power failure. UPS devices can be purchased in a variety of sizes and configurations to suit the specific needs of a retail operation.