An ARM-FIRE device for a pyrotechnic system includes a first pyrotechnic, a second pyrotechnic, a passage extending between the first and second pyrotechnics, and an actuator/blocking device positioned between the first and second pyrotechnics. The first pyrotechnic is configured to be ignited by a heat source, and the second pyrotechnic is configured to be ignited by the first pyrotechnic in the FIRE arrangement. The actuator/blocking device includes a body configured to move between a first position in the SAFE arrangement and a second position in the FIRE arrangement, an aperture extending through the body, and an actuator. The aperture is offset from the passage in the first position of the body and is aligned with the passage in the second position of the body. The actuator is configured to move the body between the first and second positions. The first pyrotechnic, the second pyrotechnic, and the actuator/blocking device occupy a volume of approximately 3.0 cubic inches or less.