Rebuilt brake booster for vintage 2002turbo BMW. "Reconditioned" or "remanufactured" means the booster has been completely disassembled, cleaned, inspected, blasted, galvanized, installed with a new seal kit, painted with 2K paint, and then tested for functionality. "ATE" is the manufacturer, and "T51" refers to the specific model of brake booster. Different versions of the T51, like the T51/100 or T51/200, exist for different vehicle chassis.