From SCP: Secret Laboratory Public Beta Official Wiki
This Template is used to represent key presses on a keyboard, and can also be used to represent mouse clicks.
Simply type the template name, then press | then hit the key you want to show.
{{New Key Press|E}} gives 
You can insert multiple keys like shown {{New Key Press|C|LMB} to get 
+ 
If you want to have multiple keys without addition signs in between them, then add chain= at the end.
{{New Key Press|C|LMB|chain=}} to get
