Lindy GMBH - Manual (Page 7)

(f) Keep pressing down on this key, and it will keep increasing
continually until the key is released.
(4) Switch Power on/off Switch.
(a) Press this Key once; the monitor would be turned on.
(b) Press this key again and the monitor will be turned off.
(c) Users are reminded that prior to press this Key to turn on the
monitor, remember to switch on your PC first
5