The guy that sold me the boat said $800 ea. But he had them mounted to cannon swivel bases and those mounted to Lund Sport trax downrigger brackets.
So you actually have these Dave.
Cool.
Cannon and a few other downrigger companies offer electric riggers that do a similar thing by raising and lowering the cannonball.
And I believe the frequency and amplitude are both variable, to a point.
I have owned electric downriggers on 2 of my previous boats and I feel they are a requirement over a manual crank rigger on deeper lakes like Ontario for trout and salmon.
But I didn't go electric on my Lund when I set it up a few years back for walleye on Erie.
My son Jeff chastised me to no end.
And he was right.
Electric riggers are NOT a luxury.
lol
Especially on those days when the fish are really hitting.
Cranking a 8-10 pound ball up from 50-100 feet down sux canal water after the 5th or 6th time.
Anyway, those units look really cool.