Adjustable step ladder 1.Material:fiberglass,super light 2.Insulated design,high strength 3.Conform to ISO9001,EN131 Adjustable step ladderMaterial:fiberglass: Advantage:1 ... .75kg/m,much lighter but stronger than the common FRP ladder which is 4kg/m.2.portable and convenient:You can ... line works and substation maintenance operations under 500kv voltage. Adjustable step ladder