As the handle says it's a US Divers Sea Hunter with the small Riffe reel. It used a unique roller sear tooth. I have a mint one in my son's gun collection, almost whiskey night cap time, so I'll tell ya more about it Wed eve. The Black custom has a very long 3/8 shaft, Al Schneppershoff had a few of them as well.
Don't try pulling the reel lock when a hot 45# Yellow is heading for deep sand , it will lock and you will hit the bottom or let go of the gun.
Many guys including me, rigged the lock to release with the trigger pull linkage.The smart ones took it off, however it's great for short lining big snapper short of the cave wall if your young and dumb, however I do not recommend this as a few have died trying.
The Riffe Reel was developed by Jay's brother and the rights sold off back in the day.