Started with a Garrett. I think I've probably tried everything make and model from 1977, all the way to the up to the E-trac and GPX 4800.
Nothing new as for me now, I am pretty much handicapped.
It looks like there is a chain run through it? I have no idea what it started out as originally but if that is a chain it probably ended up being used as an anchor and was lost. To really have a chance at IDing it you'd need to bring it up and clean the crust off.