There were two systems they used. The 'X' system, where they marked the bow at the target draw weight and put X's on it to show how far and what direction the bow deviated. One 'X' for each pound. Like a bow that drew 39 pounds would be marked x40, or one that drew 42 pounds would be marked 40xx. The other system was they simply marked the bows in the weight range the bow actually drew. A 40/45 will draw anywhere between 40-45 pounds at 28".