A left-handed mouse is designed for use with your left hand. These are more comfortable than a right-handed mouse. They work the same, but the shape and functionalities are adjusted to use with the left hand. The top 2 buttons are switched around, for example. Work on your computer a lot? Choose an ergonomic left-handed mouse, like the one from Logitech. When you use an ergonomic mouse, you keep your hand and wrist in a relaxed position. This prevents overload and RSI.