Synth relay grenade

Synth relay grenades are a type of explosive ordinance that can be found and obtained in the Commonwealth, in Fallout 4.

Characteristics
A grenade created by the Institute, it will summon a Gen-1 synth to support its user upon exploding. They visually resemble a pulse grenade, but are painted red rather than yellow.

Locations

 * Found near the shooting range in the Advanced Systems division of the Institute.
 * Acquired from X4-18 during the Battle of Bunker Hill quest via speech check.
 * Found on the bodies of, or pickpocketed from, Coursers.
 * Sold by the requisitions synth at the Institute.