... Tread 1.Metal grating 2.ASTM A123,SS400 3.Common pitch:30mm&40mm 4.Used in flooring,walkway ect. Stair TreadStair ... 8",1-1/4"x1/8",1-1/4"x3/16",1-1/2"x3/16",2"x3/16",2"x1/4".3. Stair tread ... Bearing Bar Pitches:12.5mm,15mm,24mm,25mm,30mm,30.16mm(1-3 ... : 38.1mm, 50mm, 75mm, and 100mm,101.6mm(4").5. Stair tread Standard Grating Panels Sizes: 3'x12', 3'x20', 3'x24'.