The M10 mounting arm features a 2 3/8 round (60 mm), extruded-aluminum tube, welded to a cast-aluminum clamp-on pole adaptor. Comes with a standard decorative pole cap.;The mounting arm includes a 4 (102 mm) O.D. extruded aluminum luminaire adaptor welded to the arm for luminaire mounting. The mounting arm clamp is mechanically assembled on a 4 (102 mm), 5 (127 mm) or 5 9/16 (141 mm) pole using stainless steel hardware. The location is pre-drilled on Lumec poles.