Star Trek: Enterprise, Neurolytic Restraint

original movie prop

When T'Pol and other Enterprise crew are captured by Orion slavers in the Borderland, they are restrained by these small but potent devices, easily attached to skin and producing extreme pain at the first sign of disobedience. 

Painted resin, metal wire details, orange LED activated by push button on the face of the prop.

From It's A Wrap.