My son is going to be Ant-Man for Halloween and he wants Pym Discs for his costume. This piece can be sewn onto the belt (most likely where I'll put it) or could be made into a wrist or forearm accessory with some string or elastic.

The discs lock into place with a quarter to half turn. They only fit one way, so I have to paint my second set of discs the opposite colors to show red and blue.

Thanks again to elvisior for the original design.