The DBI-SALA Advanced Hoist Systems Three Piece Portable Base 8518005 is the starting point for a versatile confined space rescue and retrieval system. The robust construction uses powder coated aluminum for amazing strength, while still being surprisingly light in weight. Easy assembly, using no tools, just line up the holes and push in the detent pins. Features include adjustable aluminum leveling screws & built in level indicator. This makes set up on uneven surfaces a breeze, with the leveling legs having nice big handles. The base disassembles and collapses without tools into 3 lightweight components for transport and storage. A carrying bag is available separately. This base comes standard in the 8518000 5-Piece Hoist Assembly. The base rails can expand or contract as needed for your application. The adjustment range is from 37 to 64 inches. So from the smallest manhole to a 64 inch wide vault opening can be handled by one device. A typical assembly will include the 8518005 base and: DBI 8518001 Adjustable Offset Upper Mast and a DBI 8518558 Confined Space Winch And while these may be typical, you are free to build the system that works for your application. For instance, with low overhead clearance, a shorter mast might be just the ticket. In addition, mounting points are provided to allow you to add a self retracting lifeline or material winch if desired. Maximum offset for the upper mast is 30 inches.