Adding on the what ManSkills said, champagne (i.e. from the champagne region of France) bottles typically take 29mm caps, while beer, soda, etc. bottles take 26mm caps. Sparkling wine bottles from California (eg. Mumm Napa), typically take 26mm caps as well. As far as I can tell, the Cali bottles are every bit as robust as their European counterparts, just with the smaller cap size.
I have a very cheap hand capper purchased from my local brew shop (I do small volumes, so this works for me). I have two bells, one 26mm and one 29mm, which are easily interchangeable.