RWRP stands for "reverse wind, reverse polarity" This refers to the winding of the pickup coil and the polarity of the magnets in the pickup. It is the "humbucking principle." When one pickup is out of phase with another TWO WAYS, that is, when the windings are reversed, and the polarity of the magnet(north and south) is reversed you get the noise reduction effect of a humbucking pickup NOT THE TONE OF A GIBSON TYPE PICKUP, JUST THE NOISE REDUCTION effect.
So if one of the pickups in any set is reverse wind, reverse polarity (RWRP) from any of the others, whenever you have it on, IN COMBINATION with another, there will be noise cancelation - but not when any one pickup is on alone.
In a strat set you can only have one RWRP pickup. If you had two, they would become the "normal pickups" because they are identical in polarity and winding, and the old "normal pickup" would act as the rwrp pickup.
This is not new knowledge, or invented by the guitar industry. Seth Lover of Gibson patented it in 1956 but it existed in transformer technology many years prior to that (I have found references in an English tech manual from 1929) The P-Bass pickup has RWRP technology.