A nearly exact replica of Russian F-1 hand grenade with a secret compartment for your pen drive.
Ring is a simple key ring, it is exactly the same size.
Pin is made of thin steel wire. Bend it to shape with pliers.
Based on this design:
https://grabcad.com/library/f1-grenade-1
Flash_Grenade_1.stl | 392.6KB | |
Flash_Grenade_2.stl | 308.5KB | |
Flash_Grenade_3.stl | 64.9KB |