Thanks to ZZDoc, he's pointed to GC's ad which describes them as :

N3 Noiseless pickups :

N3 Noiseless pickups deliver the best of yesterday and today, because they deliver landmark vintage Fender tone and response without the hum that can plague single-coil pickups. Using an improved stacked coil-coil design, N3 Noiseless pickups are specially tailored for each Stratocaster and Telecaster pickup position.

The insulated metal core of each pickup position type differs in thickness and composition for enhanced tone, and Fender has fine-tuned the sized, shape, and wire gauge of the coils to balance the magnetic responsiveness essential to great tone. N3 pickups represent a welcome return to the warmth and clarity of alnico magnets. An Alnico 5 magnet is used in the bridge position, Alnico 2 in the middle position, and Alnico 3 for the neck position.