ISO 22523:2006 specifies requirements and test methods for external limb prostheses and external orthoses, including the following classifications from ISO 9999: 06 03 - 06 15 Orthoses 06 18 - 06 27 Limb prostheses It covers strength, materials, restrictions on use, risk and the provision of information associated with the normal conditions of use of both components and assemblies of components.