The Screen Keeper system comes with a dongle receiver, which plugs into your computer's USB port. A small, low-power RF transmitter can be attached to your clothing or put into your pocket. Whenever you are within a few meters of your system it will be active and you can use it normally. Whenever, the transmitter moves to 4-9 meters away, your screen is automatically blanked and the system locked to prevent tampering. The distance at which the system is locked and blanked is adjustable over three ranges (short, middle, long). The software also allows you to let the monitor go into power-saving standby mode whenever you are gone long enough. The transmitter device will also go into power-saving standby mode whenever you are away for a while. To reset the device, simply turn it off, then back on and it will be ready to activate your system whenever you are within the appropriate range. The single CR2025 battery in the transmitter device will last about a year, based on a standard 5-days/week, 8-hours/day work schedule. For best results, the receiver dongle should be placed on top of the desk, next to the keyboard, which may require the use of a USB extension cable.