This part of ISO 9241 provides guidance for the selection of input devices for interactive systems, based on ergonomic factors, considering the limitations and capabilities of users and the specific tasks and context of use. It describes methods for selecting a device or a combination of devices for the task at hand. It can also be used for evaluating the acceptability of trade-offs under the existing conditions. The target users of this part of ISO 9241 are user organizations and systems integrators who tailor systems for a given context of use. It is applicable to the following input devices: keyboards, mice, pucks, joysticks, trackballs, trackpads, tablets and overlays, touch-sensitive screens, styli and light pens. It does not specify design requirements or give recommendations for those devices. NOTE 1 The selection guidance has been developed for the single-finger use of touchpads. Touchpads that allow the use of more fingers do exist; however, this part of ISO 9241 does not offer any guidance on their selection. NOTE 2 The only physical component of a speech-recognition system is a microphone. Without proper knowledge of the context of use it is not possible to give guidance for selection.