Hydro2Go Mixing Ball for Sports Drink Protein Shaker Cup Bottle Mixers

Seems to be better than the usual wire agitator.

Exactly what I wanted. I like to put 2 blender balls in my large bottles. Work great! You could even use it independently in a mason jar for salad dressings.

Just a bunch of high quality blender balls, exactly what I needed at a good price.

I bought these for mixing bottles of infant formula and they didn't really help at all. I ended up tossing these and buying mini wire whisk balls that work better.

does the job