NEC XP21 - MultiSync - 21" CRT Display User Manual page 13

E-8 Recommended use
The power outlet socket should be installed as near to the equipment as
possible, and should be easily accessible.
We recommend using the power cord supplied with the monitor.
However, if another type of power cord is required, power cord
H05VV-F should be used except in U.K.
Warning: Do not press the degaussing switch for more than 10 seconds.
To clean the CRT surface use a lint-free, non-abrasive cloth and an
neutral cleaner based, non-abrasive cleaning solution or glass cleaner
for best results.