From David Gage's website:
The Realist LifeLine for Bass
The Realist LifeLine™ is our newest bass pickup. Click to enlarge the bottom image to the right for instructions.
This durable, self-powered, transparent piezo pickup offers a focused bass sound, perfect for those musicians who want a lot of punch without loss of fidelity. The LifeLine performs well at high volumes, offering a clear sound without boom.
Mounted at the adjuster without glue or fasteners, the LifeLine will fit on most bridges without changing a thing, and it's just as easy to take off.
"The new pickup is really amazing. I'm totally digging the sound on stage; so much presence and no feedback problems at very loud volumes." ---Tony Garnier, Bassist for Bob Dylan