19 Slabs and webs of rubber or gum for floors being rubber flooring; construction materials, namely, non-metal materials for constructing floors, except parquet flooring, parquet slabs, laminate flooring, quartz, rock, and stone surfaces and slabs; construction materials, namely, non-metal flooring materials, except parquet flooring, parquet slabs, laminate flooring, quartz, rock, and stone surfaces and slabs; non-metal tiles; non-metal floor tiles; tile flooring, not of metal; rubber floor tiles; rubber flooring; rubber and synthetic non-metal tiles for use on indoor floors; non-metal floors, except parquet flooring, parquet slabs, laminate flooring, quartz, rock, and stone surfaces and slabs; stair treads not of metal; synthetic flooring materials or wall claddings, except parquet flooring, parquet slabs, laminate flooring, quartz, rock, and stone surfaces and slabs; base moldings for floors, not of metal; staircase construction parts, being step treads and stair treads, not of metal