The "9J-L1" is the slightly longer bridge-position pickup of the 9J 'original sound' Jazz pickups.  For a Jazz Bass, you can pair it as a combo with the shorter "9J-S1". Or for a P-J bass you can pair it with the "8S".

Full and warm deep vintage tone - The most popular dual inline-coil hum-cancelling Jazz bass upgrade pickups.

The original Bartolini design gives you the timeless tone that started it all – full and warm for that vintage voice you’ve been craving, enhancing the natural voice of your bass. These dual coil inline pickups are hum-cancelling even when only playing the neck or bridge pickup, so they are well suited for studio or stage. They have a blade core design, so you don’t have to worry about string alignment. Original Barts bring out your voice, low and clear.
In the early ‘70s, Bill Bartolini leveraged his deep knowledge of acoustics to create pickups that produce the most natural, musical voice from the instrument. He added shielding to block radio signals and noise. He developed a method of sealing, isolating, and stabilizing the coils so they could be encapsulated in epoxy to eliminate “microphonics” – the nasty noise you get when you touch typical pickups.
Available in balanced specific bridge and neck versions.

For full details, specs, dimensions and wiring diagrams check out the USA Bartolini webpage here:
Bartolini 9J-L1

NB: Prices are in NZD and include 15% GST.  For Australian & International customers the GST will be removed at checkout