"I have too many pockets!" - said no cosplayer ever
The HIPO hidden pocket from the Chalk Twins is a lightweight, modular, water resistant, tough, attachable phone-sized pocket. The HIPO comes with four attachments:
A long strap - to hang the HIPO from your shoulder
A short strap - to hang the HIPO from your wrist
A belt clip - to attach the HIPO to your waist or belt
Alligator clips - to attach the HIPO to clothing or the top of a boot