A mouse, known as a computer mouse, is a peripheral that allows users to interface with their computer via two-dimensional pointing motion which produces a corresponding graphical change to the interface. On most systems, this translates to a pointer on screen moving alongside the mouse's motion. It can also trigger further interface options such as opening and navigating menus with use of its button inputs.
In its most recognizable form, it is comprised of two buttons corresponding to a left and right, a scroll wheel which can also be pushed down to act as a third button. Originally it had a ball in roller and detects motion with its movement on the surface. Nowadays mice feature optical sensors with no moving parts. The device has appeared with both wired and recently, wireless capabilities.
Types of Sensor
Wired vs Wireless
Wired pros: cheaper, more options, don't need to charge, latency Wireless pros: portability, size, no wire
Typically a gaming and productivity mice will have 2 or more thumb buttons, typically bound to page up and page down. MMO mice are a sub category mice which includes on average 12 buttons instead of 2. This can be particularly useful for MMOs and other such high actions-per-minute (APM) games due to the ability to bind multiple independent different actions to different physical buttons.
Dots Per Inch refers to how sensitive your mouse is to movement. The higher your DPI, the faster your cursor will move.
The DPI you feel comfortable with is entirely individual, but 400 for lower than 1080p and 800 for higher than 1080p are very common choices.
500Hz vs 1000Hz
These refer to polling rates. 1000Hz is technically more accurate so you might as well set yours to 1000 but the difference is so imperceptible to humans you can't really go wrong with either.