The vertical design of the ergonomic Penguin Mouse Small means that your forearm and wrist are placed in a natural, neutral position while you're working with the mouse. Your hand is supported properly. Because the Penguin Mouse is also symmetrical, you can use it and alternate between your left and right hands. This allows you to distribute the workload more evenly between both hands. The Penguin mouse is easy to use. The scroll wheel is extra large and made of fine rubber. The 'bow-tie' switch near the bottom is used to switch the mouse between right and left handed use. Moreover, all the buttons on this mouse have soft key touch, which means that you only experience a slight resistance when pressing the buttons. The Penguin Mouse Small is most suitable for those with a hand-length measuring from 140 up to 160 millimetres. You should measure your hand from the beginning of your wrist to the tip of your middle finger. The Small version of the Penguin Mouse is 124 mm long, 99 mm wide, and 76 mm high; it weighs 146 grams and its cable is 150 cm long. This ergonomic mouse is coloured anthracite and silver. It has an anti-bacterial coating. The resolution can be adjusted to 400, 600, 800 or 1200 dpi. It is plug and play and compatible with Windows XP, Windows Vista, Windows 7,8 and 10; Mac OS X v10.5 and later.