We bought this sterilizer in conjunction with the NUK First Choice bottles and had to go to the third sterilization notice that a bottle had totally deformed. Amazon has this replaced immediately without hesitation. Stood on the Amazon page, that this sterilizer can be used for all NUK First Choice and commercial bottles. On the homepage of NUK we then small read somewhere in parentheses that this sterilizer is not used for the NUK First Choice bottles from PA.