A white or amber LED (depending on model) is located on the top edge of the display, illuminating the keyboard to allow use in low-light conditions. It is activated with the key combination "Fn-PgUp" (the bottom left and top right keys of the keyboard). Later ThinkPads use the combination "Fn-Space" instead. Lenovo later started to include backlit keyboards, and some models included both the ThinkLight and a backlit keyboard. For those models, the "Fn-Space" shortcut is also used in conjunction to control a backlit keyboard (if the laptop has it). The on-screen display of ThinkPad computers will display a light on and a light off indicator. The ThinkLight can be activated when the monitor is on or off but not while the computer is off.