Review on 🥤 YOFAN 5 Pack Formula Mixers - Milkshake Protein Shaker Balls for Small Bottles - Food Grade Stainless Steel Wire Mixers - Perfect Mixing Ball for Small Shakers & Drinking Bottles (5-Pack) by Fock Dean

Was asked if you can use them with standard Dr.Brown bottles, yes. You can't just drop it, you have to press it with your finger, and to pull it out when you're cleaning the bottle, just shake it well and it comes out just enough for you to pick up with your fingers. You can't leave the shaker in the bottle when using a Dr.Brown colic vent tube, neither are good for getting around this. I just mix it up in another bottle with a shaker ball and pour it into Dr. Brown's flask. I like to use these shaker balls when I take my pre-mixed bottle with me because it doesn't take long for the formula to start setting, so I just pop one in when I do and then when I'm ready pop them in to use a few hours, i just shake it a few times to mix it up. They're also great for when you start mixing rice flakes into your mixture so there aren't any lumps left behind and sinking to the bottom. I don't recommend shaking it back and forth quickly as this will cause the formula to foam and create air bubbles. To prevent this, I only move the bottle back and forth very slowly to mix it. They're easy to clean by throwing them in the dishwasher, I clean them with a bottle brush when I wash bottles, and I also throw them in a bottle warmer along with teats and other bottle parts to steam and sanitize. Never had a problem, they kept their shape.