Refurbishment is the distribution of products (usually electronics and electricals) that have been previously returned to a manufacturer or vendor for various reasons. Refurbished products are normally tested for functionality and defects before they are sold. It is repaired from the manufacturer and resold.
The main difference between "refurbished" and "used" products is that refurbished products have been tested and verified to function properly, and are thus free of defects, while "used" products may or may not be defective. Refurbished products may be unused customer returns that are essentially "new" items, or they may be defective products that were returned under warranty, and resold by the manufacturer after repairing the defects and ensuring proper function.