A wireless presenter is a handheld device used to control and enhance a presentation given using a projector They allow you to move freely and highlight important details to the audience.
Wireless presenters usually come with a separate USB transmitter to plug in to your laptop or PC. You can then use the controls on the handheld device to switch between slides without having to return to your computer every time. Most wireless presenters have a built-in red laser pointer to allow you to emphasise specific areas of a presentation.
As the devices are wireless, they operate with batteries that need to be replaced. Wireless presenters tend to be lightweight and ergonomic.
The main difference between wireless presenters is the distance at which they are effective. Some only operate over a short range, like a classroom, while others can be used over a bigger area. LCD screens on some devices indicate things like battery power, signal and time remaining. Discreet vibrating alerts can tell you when your time is up.