This Specification outlines the requirements to furnish and deliver Traction Motor Bellows, Pittsburgh Regional Transit (PRT) Stock # 162019, as manufactured by Gray Manufacturing Industries (GMI) part number A21-0002, or “Approved Equal”, for PRT's light rail vehicles (LRV) as specified herein. The contract duration shall be two (2) years from the date of Notice to Proceed. Purchase orders for the Traction Motor Bellows will be issued periodically over the duration of the contract. PRT estimates that it will order two hundred (200) Traction Motor Bellows over the two-year contract duration. PRT may issue purchase orders for a quantity of fifty (50) Traction Motor Bellows about every six months. It shall be understood and agreed to that the total two-year quantity of 200 and the estimated purchase order quantity are estimates that may increase or decrease in accordance with inventory re-order points and corresponding replenishment values.