They are modeled after the Custom Bucker pickups in Gibson's Custom Shop guitars. I have a Gibson Custom Shop 335 and a Custom Core with 225 Pickups. They are nearly identical, both sets use A3 magnets. Edwin Wilson came from the Gibson Custom Shop to oversee/engineer the Custom Core line for Heritage, so he brought the Custom Bucker humbucker model with him. The 225s are a vintage PAF clone, the HRWs are much hotter. The 225s and HRWs are completely different animals. I liked the HRWs in my Golden Eagle Jazz box, but I didn't like them in solid body 150s or Semi-hollow 535/555 guitars.