I raised my daughter and son with a combination of breast milk and formula. Because of this, I used these bottles every day, but they are made of glass, so there isn't much scratching or deterioration. The 100ml bottle is the same as the one I used at the hospital, and it was easy to use because newborns only drink small amounts. These baby bottles are keepsakes, so I hope they can be of use to someone. *Please note that the parts and lids have been disposed of.*