Radio shack brand?
not sure but it looks exactly like the one that I first ever saw,
that sparked my interest years ago, (about 1978) but didn't persue....
My dad borrowed one like it from a friend,
and we did some Thanksgiving day treasure hunting
on my Uncles' farm in the woods of Missouri.
Interesting... my brother in-law that drives a garbage truck,
found a detector last week, a Garrett GTA 350 complete !
With the box and directions, ( minus head-phones )
I put it all together, some one left the batteries in it
the to battery clips were cracked, and corroded
I cleaned up the insides, put in my extra AT PRO clips & it fired right up!!
A friend of mine has an old Garrett ground hog
He believes the coil on it has gone bad,
maybe he'll want to upgrade ?