Radial Grate tread is available in steel, aluminum, or stainless steel and can be incorporated into all kit and fully assembled spiral stair models. Radial grate construction consists of 1" x 3/6" flat bar with ¼" x 2" frame make for a very ridged and effective step. Radial grate tread offers all the benefits of a traditional bar grate step, while keeping a very contemporary clean finish. Great for areas with snow and ice, this spiral staircase step does not sacrifice functionality for aesthetics.