Detonite Injectors are a resource which can be researched in and obtained from the Chem lab of your clan's Dojo. As such, they are also most commonly used in crafting of Grineer arsenal items, however, they are not restricted to this purpose. Blueprints for Detonite Injectors can be purchased from the Chem Lab terminal 15,000 once it has been researched. Otherwise, they can be obtained in a fully crafted form from Invasions, Rare and Reinforced Grineer Storage Containers, as well as Grineer Reactor Sabotage missions.