... :C. Hey, if you do not understand the above table for stair tread, do not worry about it ! I am sure you will make it ... are “600,700,800,900,1000 “ right? Well, I think it is more easy for you to understand. It is the outside specification ... 305 x 700.Well, I think that you could understand the specification for the grating stair tread.And after you make it clear of ...