Although there still are the larger Presenter Logitech and allegedly again has twice the range, the range extends from the already well-R400 in 90% of cases. The range is significantly greater than 10m and the principle even works through doors and averted gaze direction with obstacles / walls. The service is also great because in addition to the forward and backward keys or one key for presentation start / finish and a black screen for switching exists (I personally find very good). The USB flash drive, which is integrated in the Presenter is simply plugged into the laptop / PC (tested with Windows XP) and without any additional software installation you go then go. A green icon indicates a battery sufficient battery backup. The red laser pointer is also pretty good and strong, or even visible on longer distances. The slider on the side of the device is used for switching on and off and ensures that the (enclosed Duracell) batteries are depleted unnecessarily quickly.
