The primary function of a bracket is to have a good right angle, which is not the case that I received. Of course it has other functions, but mostly I wanted to use me square and on this side I am VERY DISAPPOINTED. The plastic stop is somewhat crowded so that one track of the different traits in each case. Unable to trust and I lose time to re-measure each time my ribs. 40 cm there is between 1 and 2 millimeters apart. Otherwise good, just a little heavy.