Tolerances are + 0.1 mm Material... Most softwoods are suitable.
Like all wooden frames intended for use in bee hives, there are many variations... The types illustrated below are the most common.
I do not recommend the 8 mm x 6 mm version as it is too flimsy and can warp badly. The twin Manley type is probably the most common, certainly I was asked for them most often when I was in the beekeeping equipment supply business.
there is a 22 mm wide single version that is similar in all other respects to the one at the bottom of the drawing.