Stiffness Tester Model 108 is based on the torsion apparatus described in test method ASTM D2821 Standard Test Method for Measuring the Relative Stiffness of Leather by Means of a Torsional Wire Apparatus. It is used to measure the flexibility and stiffness of a leather or other bendable specimen and has been shown to be a reliable method of evaluating the relative stiffness of leather used in gloves.

Simple to use, rugged design provides repeatable test results. Mounted to a rigid stand, the instrument consists of a torsion head, fixed torsional wire and specimen clamping system. A specimen is affixed to a weighted clamp secured at the bottom of a torsion wire. A torsion head equipped with a dial protractor is turned in a plane normal to the torsion wire until the specimen has been twisted 90°. Torsion values are obtained by measuring the applied angular twist required to reorient the sample 90° or some other specified setting.