A Marine corporal may have come up with a brilliant way to treat a gunshot wound the moment a bullet pierces body armor.

Cpl. Matthew Long, a motor transport mechanic, designed a tear-proof package filled with a cocktail of blood clotting and pain-killing agents that sits behind body armor, which would be released instantly if pierced by a bullet. Though Marine body armor, called “flak” jackets, come with small arms protective insert (SAPI) plates to stop bullets, they can have trouble stopping multiple rounds.

Long’s invention, if fielded, would render first aid immediately, without a Marine having to do anything. The seemingly-simple tweak could save lives when a medic is not immediately available.

The corporal was selected as a winner for his invention in September during the Corps’ Logistics Innovation Challenge.