This is so convenient! It's so easy to attach directly! I've tried other baby bottles, but I thought, "This is so troublesome..." and I kept using this one until the end, replacing the nipples. My child wouldn't accept any other baby bottles, so we used this until weaning. The nipples are old, so please purchase them separately. You can buy them on Amazon^^ On Amazon: 100ml x 2 bottles + 2 caps + 2 nipples = 2500 yen 200ml x 2 bottles = 2478 yen I will ship via Eco-Mercari.