I was going to buy a few Avent disposable bottles for travel, but having to buy separate nipples made it a waste of money. Then Avent came out with these!I like how you can use the regular nipples and these are cheap enough you can just toss them (especially great when you find it two weeks later until the seat). :c)Also get the extra refill pack. You can use these all of the time. I also have the regular bottles, too, for home.