Minimum inside width of bow proof force :0,5 t up to and including 2t:+1,5/-1 mm 3,25 t up to and including 12 t:+/- 2,5 mm 13.5 t up to and including 25 t:+/-3 mm Allow bow diameter d, to be oval, + 10 % for sizes 3,25 t up to and including 17 t, + 25 % for size 25 t (same tolerances as above) Inside width at pin,Wn :0,5 t up to and including 2t:+/- 2,5 mm 3,25 t up to and including 9,5 t : +/- 3 mm 12 t up to and including 25 t:+/-4 mm