I received this hoop yesterday and my son helped me with assembly. Seeing that there are 42 balls and 42 magenets... I just placed one in each ball. I've never hooped before so I was pleased to be able to go for over two hundred revolutions at a time, and I know that practice will get me there to 10 minutes. Now for the ouchie part. Massage balls??? Nothing massaging about them so far as I can tell, more like torture balls. I only hope that in time they will be less painful. All on all I like it ok. I have already ordered a ridgeless heavier hoop to alternate between the two. Hooping is fun, they just need to work on the comfort factor of the balls.