ISO 1938-1:2015 specifies the most important metrological and design characteristics of plain limit gauges of linear size. ISO 1938-1:2015 defines the different types of plain limit gauges used to verify linear dimensional specifications associated with linear size. ISO 1938-1:2015 also defines the design characteristics and the metrological characteristics for these limit gauges as well as the new or wear limits state Maximum Permissible Limits (MPLs) for the new state or wear limits state for these metrological characteristics. In addition, ISO 1938-1:2015 describes the use of limit gauges. It covers linear sizes up to 500 mm.