3M DBI-SALA Davit Arm Systems are designed for manhole and confined space entry/retrieval applications. These units are constructed of lightweight materials, including high-strength aluminum. The davit pivots for ease of rescue and has adjustment for overhead clearance restrictions. The lower base adjusts to fit most standard entries. Many other portable and fixed bases are available to suit any jobsite need. www.3m.com/3M/en_US/p/dc/v100869192/