Model of a non deployed Ember Celica belonging to Yang Xiao-Long from RWBY.

This was specifically designed to be a comfortable prop for cosplay. Small, light and easy to put on and take off. Alignment holes are provided so each piece can easily be placed in the perfect space and magnets can simply be dropped in to make putting it all on very easy.
Unless you make your part with a friction fit the magnets will be required to keep it all together.

Assembly is straight forward. Simply glue small 8mm magnets in all the holes and glue the middle ring to the outer shell. Measure the widest part of your wrist to confirm what size inner ring you need. You will not need to print all three inner rings, unless three people want to wear them of course.

To put the prop on your wrist, attach each side of the inner ring around your wrist (held in place with magnets) and slide the inner ring assembly into the middle ring which will hold itself in place with yet more magnets.

edit: I messed up the sizing on the inner rings. Didn't realize until the first was printed off so I need to remove the larger sizes as they are highly inaccurate. 50mm will be re uploaded so feel free to use that one if you also have very small wrists. I'll work on getting the larger sizes uploaded soon