Manufactured from hardened and polished steel, the blades are precision milled for optimum accuracy when measuring internal and external radii. Enclosed in a steel case. | | Size range: | 34 Blade Metric: 1.0 to 3.0 x .25 and 3.5 to 7.0 x .5 | 32 Blade Metric: 7.5 to 15.0 x .5 | 32 Blade Inch: 17/64” to 1/2” x 1/64” | 30 Blade Metric: 15.5 to 20.0 x .5 and 21.0 to 25.0 x 1 | 30 Blade Inch: 1/32” to 1/4” x 1/64”.