6 Things to know before buying Durometers USA (United States) !    1. What are Durometers USA (United States) and how it works? Durometers USA (United States) are portable instruments for measuring hardness. It’s a measurement tool. It has a testing procedure for using it. It’s a specialized, self-referencing scale for comparing the hardness of a comparable group of materials. Note: Durometer USA (United States) Hardness measurements are unitless. This is the main reason comparing hardness between different Durometer hardness scales is not recommended. Though these sorts of charts are widely available, comparing differen...