ISO 3601-5:2015 contains the material specification of a selection of standard elastomeric materials (rubber) for O-rings used in general industrial applications. It also indicates the ability of the materials to satisfy many of the requirements associated with fluid power components. Only materials which are in universal usage are specified; other compounds are available and can be used. The required physical properties and test methods (including test specimen) should be agreed upon between equipment manufacturer/user and O-ring manufacturer/supplier.