The faithfull depth gauge is a versatile tool that allows the angle and depth to be measured simultaneously the protractor features deep etched graduations 0 180 in opposite directions permitting the reading of both the direct and supplementary angles the rule is graduated in both imperial and metric dimensions up to 150mm 6in and a knurled thumb nut allows the rule to be locked at the chosen angle blade length 150mm 6in graduations 05mm or 64ths