I have two of these and really like how they work. These enable you to easily lift your entire downrigger up to access the ball. I like it for my Depth Raider rigger since it's difficult to use a retro ball retriever on it. Problem is, I mounted one on my boat before discovering that I cannot access the back hatch of my boat. Dangit.
These sell for over $80 most places. I'll sell them both for $50. One is brand new, the other is almost brand new.