Filler panels can be the same color as the stair or a complementary color. Treads: Diamond plate tread provides a solid tread surface with raised diamonds for a non-skid effect. Concrete pan tread has a wrap-around front diamond tread plate nosing and arrives ready for site-poured concrete. Available in depths of 9-3/4"', 10-15/16'' and 12-1/8''.