wrist band weights

I stomped over this http://www.hoopskills.com/vbands/ (wrist band weights).
have you guys had experience of using it?
My boys don't pound the ball hard enough. I wonder if these 1/2 wrist band weights will help if I let them wear while doing dribbling excercise? or will it cause harm?

I have used them during workouts.

One tip. Do the exercises with the V band. Then afterwards, do the same exercises without the V band.

If you continuously do the exercise with weights and never without, it will actually train your nervous system to move slower.