I have two 1520 new as spares, waiting in their boxes, but I don't need them, my first 1520 still works like a charm in my mbx5T truggy since one year of intense racing and bashing on 6S .
I Still have the same bearings, love the durability of thoses NMB oversized bearing
Inferno VE MMv3 NEU-CC 1515/1Y 4S "Flying machine"