An ordnance fuze having a selector rotor and an arming rotor initially held in an unarmed position by a rod which can be released by the rotation of a wind vane to move clear of the arming rotor and thus free the arming rotor to rotate to an armed position. A timer revolves a plate to block the movement of the rod after a predetermined time lapse if the vane has not already released it, thus preventing the arming of the fuze. An externally operated control limits the movement of the rod to either permit or prevent rotation of the selector rotor to direct the blast of the primer to either an instantaneous detonator or a delay detonator.