RFID Card Armband Holder

This is an armband holder for standard-sized (i.e. roughly credit card sized) RFID cards. The STL file is for one half of the holder; print two copies to make the complete holder. When the two halves are placed together, there is a pocket to place the card in, and the halves will "lock" together with the pins in the corners -- there are matching holes on the opposite corner. Loop some wide elastic band (sew or hot-glue the ends together) or velcro through the slits on each side to make the a