The ergonomic Bakker Evoluent D Vertical Mouse M supports a natural hand position and thus minimises pain and tension. Size: Medium: (178-198 mm between wrist and the top of the middle finger) Compatibility: Windows 7, 8, 10, OS X 10.5 and later Other sizes plus wireless M and L versions available. A mouse pad is recommended when using a vertical mouse. BakkerElkhuizen guarantees the longevity of its products. Register your product before the basic warranty expires on the manufacturer's website using the registration code or the EAN number on your product for an extended warranty of up to 5 years on electronics or even longer warranties on non-electronic products! * Extended warranties apply to all non-electronic products with the exception of all gas spring parts, which are covered by a 5-year manufacturer warranty.