Micro-detonator
A micro-detonator was a small explosive device used by Starfleet in the 22nd century. 

In 2151, Commander Charles Tucker III used micro-detonators to blow up s impulse engine, to act as a signal flare to notify  to rescue him and Lieutenant Malcolm Reed, who were rapidly running out of air. ()

See also 
 Micro-charge
 Micro-explosive
Explosive weapons