ISO 16900-5:2016 specifies the characteristics of breathing machines, metabolic simulators, RPD head forms/torso, RPD tools and RPD verification tools that are common to RPD test laboratories. Standardization of these items is essential for the standardization of the test methods. Standardization of the RPD verification tools is essential for demonstrating the delivery of comparable results in different test laboratories. Descriptions on the use of the RPD tools for the different tests are specified in the relevant parts of ISO 16900.