Manufacturer refurbished units are guaranteed have less than 20 hours of use, and most have less than 3 hours. They are clean condition with occasional paint fading scratching, but most look brand new. Units have minor issues that are fixed to the same strict standards of new units.  Each unit is fully tested on load bank for performance.  Life expectancy of this model with reasonable care is 3000-5000 hours. Guaranteed to work like new, free DOA replacement.