AM6 Pole is made from a one piece, seamless 4" round (102 mm) tube of extruded-aluminum welded over and in a 6-5/8" round (168 mm) extruded-aluminum pole base. The assembly is welded to both the top and bottom of a cast-aluminum anchor plate. A 4-1/2" by 10" (114 by 254 mm) maintenance opening is complete with cover and copper ground lug. AMT6 Pole is made from tapered 5" to 4" (127 to 102mm) round aluminum shaft welded over and in a 6-5/8" round (168mm) extruded-aluminum pole base which is welded top and bottom to a cast-aluminum anchor plate. After tapering and welding,the entire shaft assembly is heat–treated to T6 temper. A 4-1/2" by 10" (114 by 254 mm) maintenance opening is complete with cover and copper ground lug. SM6 Pole is made from a one-piece, 4" round (102 mm) high-tensile carbon steel shaft sealed by a rolled and flattened vertical weld seam and welded over and in a 6-5/8" round (168 mm) high-tensile carbon-steel pole base. The assembly is welded to both the top and bottom of a steel anchor plate. A 4-1/2" by 10" (114 by 254 mm) maintenance opening is complete with cover and copper ground lug.