This is the little bit of gear that I've needed ever since installing my K&K Rockabilly Bass dual pick-up system (bridge and finger board).
Up to now, the signals from the two pick-ups are kept apart using a stereo jack.
The two are then mixed (volume only) in a pre-amp box and a mono feed sent to my amp.
Now, the finger board or click signal can be fed to a separate mono lead and sent the PA for a better click sound. This also leaves the amp to deal only with the bridge pick-up signal, fed via another mono cable. Cool.