Hi, welcome!
There are various types of juggling balls, with different weights, sizes and material, you need to find the ones that better suit your style of juggling.
Here are some links that helped me when I was searching for my ideal juggling balls:
http://juggling-for-beginners.com/juggling-balls/
https://en.wikipedia.org/wiki/Juggling_ball
by Pedro Pessotti, in response to this post 2015-12-11 22:55:25