From David Gage's website:
Realist Docking Station for Bass
Universal Volume Attenuator
Designed by David Gage and Ned Steinberger
The Docking Station solves jack mounting problems, too. The cable is dressed away neatly from the ¼” input/output without additional hardware. The tension of the strings holds The Docking Station to the tailpiece, like the “loop” from the industry standard Realist “Copperhead” pick-ups. Works with all pick-ups, no batteries required, a passive system.