mini IIW-2 measures 1 thick x 2 tall x 6 long, and contains both 1 and 2 radii. Two sensitivity holes, one at 1/16, and one at 1/8 are located 0.500" from each scanning surface. A large 1.000" diameter through-hole is included, along with a convenient step measuring 0.500" thick in one corner. Angle beam exit markers from 35 to 75° are machine-engraved on one face. Don't miss that this block also includes three close-tolerance steps for thickness calibration. (0.500, 0.750, and 1.000”)