Structures not of metal, namely, portable free-standing structures, free-standing barriers, free-standing perimeter protection barriers, free-standing work platforms, free-standing stair scaffolds and free-standing stair towers; Transportable buildings not of metal; Non-metal scaffolding and parts thereof, namely, stair treads, fixing and fastening devices for use in fixing or joining pipes and tubes, guard rails, tubing, pipes, pipe connectors, tube and pipe fittings, fittings for joining tu...