[@Gisk] Having numenera on you is allowed. The nature of what they do is up to you, as long as they aren't 'overpowered'.  Even then, you can have a very powerful numenera device that only works once.

What do you want  your numenera to be?

Note: In universe numenera that only work once are called [color=0000FF]cyphers[/color]; numenera that work multiple times are called [color=0000FF]artifacts[/color]; and numenera that do something weird and are practically useless are called [color=0000FF]oddities[/color].  
(Just in case it comes up)