3M DBI SALA HC Davit Mast Extension (21"-57")For a mast extension designed to be used in conjunction with 3M DBI SALA Confined Space HC (High Capacity) Davit Arm, use 3M DBI SALA Confined Space HC (High Capacity) Mast Extension. The mast extension is constructed primarily of custom extruded aluminium and cold drawn steel and finished in a mixture of hi visibility green and zinc plated coatings. It can be interchanged with other 3M DBI SALA Confined Space HC (High Capacity) Mast Extensions to