I received this as a gift, but I haven't used it, so I'm offering it to anyone who needs it. It's a new, unused item, but it has been stored at home, so please understand that. I can't read Korean, so I can't translate the description in the picture... but it seems you set the bag as shown in the picture and use it as disposable, and the baby bottle can be reused. The baby bottle is made of plastic. I will ship it via either Yu-Yu Mercari Bin or Raku-Raku Mercari Bin.