6 pcs steel adjustable parallel block set for accurate measurement

due to their adjustable characteristics, they can be adjusted to the exact size by micrometer measurement, and can replace multiple solid parallel pad. these parallel pads are just as useful as gauges when checking the dimensions of the slots and holes. this parallel pad can slide smoothly and is easy to adjust. smaller parallel pads a, b and c are locked with one screw, while large parallel pads d, e and f are locked with two screws. the adjustment range from 3/8in~2-1/4in for large range measuring..syi