硬度計是測量物體硬度的儀器，表示材料抵抗硬物體壓入其表面的能力。它是金屬材料的重要性能指標之一。一般硬度越高，耐磨性越好。根據所測硬度單位：洛氏硬度計、維氏硬度計、顯微硬度計、布氏硬度計、邵氏硬度計、巴氏硬度計、里氏硬度計、韋氏硬度計、肖氏硬度計、布洛維硬度。根據使用方式：便攜式硬度計、臺式硬度計。

進口硬度計，美國Check-Line RX-2100，快速測量汽車、輪胎的硬度。

The Checkline RX-2100 Tire Durometer allows racers to quickly and accurately make checks of tire hardness. Unlike other "racing durometers" (which are just relative hardness gauges), the RX-2100 is calibrated to the ASTM D-2240 standard for durometer hardness and is NIST-Traceable. Thus, the RX-2100 allows comparison with the factory tire specifications.

The Check-Line RX-2100 is a handheld gauge weighing only 4.2 oz. The indicator case, bezel, and barrel are all billet machined aluminum. The gauge is furnished with a carrying case and a one year warranty.