... systems 2.4 running lines. 3. Delivery:7-30days. Stair tread is made of steel grating, & widely used for different types ... by different nosing & installation.Type of Tread T1: Without Nosing, Welding fixing;Type of Tread T2: Without Nosing, Bolted fixing;Type ... of Tread T3: Vertical Striped Plate Nosing, Welding ...