Yep! it's the 'computer' from a VDO Adis 360 fluxgate compass. I had one for about four years and it was superb BUT, when the compass head, fitted in the cockpit (obviously) failed, VDO happily informed me that they didn't make it any more!
As the thing was only four years old I was pretty p**ed off, so they knocked a chunk off the cost of its replacement which I bought and still use. It's an excellent bit of kit.
The computer bit you have, was used to 'tune' the fluxgate (turning through a couple of circles etc) which the latest one does automatically.
So I'm afraid it's no use to you unless you or someone else has the relevant complass head.