Posted By John Ridd James, I'm not sure what sort of endorsement you might be seeking, but if it's scientific evidence of the benefit of these accessories then this might be a little difficult to find. In general the thinking is that these rests should not be provided (without good reason) since if 'used' during keyboard or mouse operation, they are likely to restrict upper limb movement (and hence increase the risks from static loading) and usually resulting in excessive reaching to the keys, or accommodating the necessary mouse movement at the wrist joint alone. The idea should be to take up some of the necessary movement at the shoulder, some at the elbow and some at the wrist - this is only achievable if the arms are 'floating' freely above the keyboard. By fixing the arm at the wrist (on the wrist-rest) all reaching has to occur at the wrist! This goes against good design principles which recommend reducing excessive joint movements. That said, such principles are directed at intensive typing situations; these days, many users of keyboards are required to enter only short pieces of text before interruption, and the risks arising out of a 'rested' wrist in these circumstances are that much less. Situations where the use of a keyboard rest can be advised include where a worker has been assessed as having a bad wrist posture (e.g. they already rest on the desk while typing) - perhaps a wrist-rest would help them to attain a more appropriate forearm/hand typing posture. Also, where the hand is often held over the cursor keys or numeric pad; rather than support the arm in space, or on the edge of the desk (causing static loading or pressure) a wrist-rest might be appropriate. Wrist-rests for mouse use are less easy to justify, as, if the mouse is used to the extent that one might be necessary then it is probably the wrong device for the task in the first place. Again and for similar reasons as described above, it is argued that the mouse should be used with the arm/hand not rested at all - but this guidance was developed for early 'Windows' operations where RELATIVELY few mouse functions were necessary. In today's office with the emerging software and tasks required, this practice is not realistic. Hence the aim should be to reduce exposure. Train users to use the left as well as the right hand for mouse operation; train them to use the keyboard commands, provide other non-keyboard-input alternatives as options - e.g. touch pads, trackerballs, mouse pens, the 'Roller Mouse', the 'MouseTrapper' etc. etc. Finally, I would make the point that many of these devices, when overprinted with text and logos, offer a rough surface to the user - this can and usually does cause irritation leading to non use, even when the device may have been beneficial.