This is a handmade pickup from the lovely chap Michael Zadow.
I ordered this especially as a backup for gigs where I was worried about feedback. The magnetic pickup is big, bold and strong and looks the business in gold!
It's held in place with velcro, and the jack socket is held in place under the pickup this way. It's actually a really good system.
The pickup is a couple of years old and while it's sat on my bass for lots of gigs, it has hardly been used.
You can learn more about the system here: https://www.zadow-electronics.de/pickup_e.htm
Was thinking around £140, but I'll let you decide. This has been replaced by both a copper head and a Nadine, both of which has (so far, at least) worked without feedback.
(To note, you'll need to use strings with a metal core or the pickup won't work.)