For the technician that must perform hardness tests on various types of non-metallic materials,Rex Gauge Company provides the Multi-Scale durometer test kit.The Multi-Scale base kit consists of a Rex A scale durometer, and your choice of one or more color-coded barrel adapters for D, B,C, DO, O, OO, OOO, or E scales(see the quick reference guide on page18 for applications). Changing scales is accomplished by unscrewing one barrel and replacing it with another - no supplementary calibration or adjustments are necessary.A test block, calibrated to the selected scale is also included. The block allows the user to perform quick, functional checks on the instrument. The indicator and barrels are made in the USA, and are calibrated to the ASTM D2240 standard for durometer hardness testers.