These shaker bottles are by far the most amazing bottles I have ever used. On the side it tells you how much to put in the bottle in mL. They are super cheap and can be found at a lot of stores. Plus they are dishwasher safe so when you want to get the extra clean you are able to! You can get them in any color so it really is nice to mix and match things. I have at least 5 bottles in all different sizes. I would for sure suggest you to buy these bottles!