27.5In Manhole Collar For Use On Manways Base Installation Portable Brand and Series 3M DBI-SALA Advanced Color Green Compatible Component Lower Mast Extension One-Piece Arm Confined Space Component Base Confined Space Item Base Diameter 27 1/2 in For Manhole Dia 28 in to 30 in For Max Manhole Dia 30 in For Min Manhole Dia 28 in For Use On Manholes Includes Carry Handles Yes Material Aluminum Mounting Location Manhole Mounting Type Clamp-On Series Advanced