Speaking of gadgets, what if some sort of finger brace or sleeve or athletic tape, even, was put on the index finger to restrict it from bending until a batter felt the benefit and formed the right habit? Wouldn't that be similar?
I was thinking with the BatJack on the bottom hand the batter could really swing fast without fear of the bat coming out of their hand. Some batters can't get rid of that concern.
The Bat Jack doesn't restrict the index finger from bending. It creates a natural angled grip in the correct gripping fingers. The biomechanicaly correct design allows for a comfortable adjustment and an instant improvement to the performance of the grip.