This 14'' set gives you both straight and rounded calipers to measure with Inside - Outside - and Divider. Locking screw mechanism assures accuracy. Adjustable screw is about 3'' long and the knob is about 1/2'' to make overall screw length of 2 1/2''. Outside caliper opens to about 11 1/2'' max. Package Dimension: 6.5'' X 15'' X 1''