Complete subsystems as follows: a. Individual rocket stages, not specified in 2.A.1., usable in systems specified in 19.A.; b. Solid propellant rocket motors, hybrid rocket motors or liquid propellant rocket engines, not specified in 2.A.1., usable in systems specified in 19.A., having a total impulse capacity equal to or greater than 8.41 x 10 5 Ns, but less than 1.1 x 10 6 Ns.