A hand-operated pyrotechnic device has a tubular handle and, slidable telescopically therein, a tubular striker supporting a firing pin. The striker is rotatable from a `Safe` position to an `Armed` position, and movable axially, by impact, from the `Armed` position to a `Fire` position. A resilient detent prevents movement from the `Armed` to the `Fire` position unless the applied impact force exceeds a predetermined value. Further resilient detents prevent unintentional arming of the device.