Looks like the exact ones I bought are not on amazon anymore, but i used ~3mm balls. The ones in the link below will work, but it is way more then you need. I think I ended up making a few for friends at the time.
Might need some kind of funnel to fill the bag, I think I used the meat stick attachment on my sausage stuffer with a stick to push them in.
Amazon product ASIN B07QGZ8PD9
