The f5 Designs flat beads are 3D printed beads for 3pcs 1.5x6.0mm tritium vials. The vials are inserted via the lanyard slot and there is no visible clue to their installation method when the bead is on a lanyard.
Options for color variations are (almost) endless, with the eyes being lit from one vial and the "grille" from two vials.
|Prototype Cyber Bob. Even madder with a red trit for eyes...|
Cyber Bob can be purchased here: http://shpws.me/ozGY
Also check out Angry Bob here