I,m sorry if the number was incorrect but I read it directly from the valve, 5 and S look very similar cast in tiny figures on the casing !

The beauty of these valves is that they open only when pressure is applied so when the pump is off the valve stays closed and the gear remains locked.

I have not not yet installed these valves in my Mig 29 but presently the gear is locked by manual Festo valves adapted to be servo driven and controlled by a JetTronics sequencer, works very well but the newer Festo valve will eliminate servos etc and reduce risk of failure or incorrect sequencing.

David.