The PRO-3 Series Hoist System is designed to provide an anchor structure for Personal Fall Arrest Systems (PFAS?s),Confined Space Entry / Retrieval and rescue equipment. Provision is made for the mounting of various winches and SRL?s to the structure on the rear of the vertical post. Other mounting options are possible using a variety of adaptor brackets available from Tuff Built Products. 1- and 2-piece Davits are available in a variety of heights to tailor a system to your specific application requirements. Upper mast refersw to as upper portion of Davit which is available in various dimentions and fits to the lower mast to offer different height and reach. lower mast of Pro 3 davit is the lower or middle portion of davit which fits into the base from one end and upper mast on the other end. available in two sizes which give different height and reach to the davit system