This is a modern design dual coil humbucking pickup. Pickups like these are usually found on very high end basses. They use Alnico V magnets and the traditional bi-pole layout with two poles per string. It’s almost like two Jazz Bass® style pickups in one cover.
These pickups are available in two different versions. One set is designed to be wired in parallel, and the other in series. The reason Nordstrand does this is that a pickup that is made to sound good wired parallel will usually be too hot and dark sounding if wired in series. So, Nordstrand puts less wire on a series dual coil than a parallel dual coil. In general, a pickup wired in series will have a fuller and fatter midrange with a subdued high end than a pickup wired in parallel, which will typically have more highs and a deeper low end with a cleaner midrange. Series pickups also have more output than parallel pickups. Parallel pickups are generally a better choice for a split-able installation, as there will not be the gain loss associated with series pickups.
These pickups are available only in black plastic covers with exposed pole pieces.