swing top bottle in Google images, this site show the 'mechanical' of a single swing top
http://fr.fotolia.com/id/9368625

This, there lots of them  

http://images.google.com.br/images?hl=pt-BR&q=swing%20top%20bottle&um=1&ie=UTF-8&sa=N&tab=wi

I read about it in the net and I learned that:

Some disadvantages ->

-They are more  expensive (royalties over the invention and all that stuff)
-They are made with thinner glass and don´t withstand great pressure (of carbonated
and fermented drinkings for example) so they break.

Some advantages ->
-At the sea you don´t lose your beer, or drink, when you forget a laying bottle, or if
it fell of the boat you will see it floating (provided that you capped it in advance).
-You can reuse it.
-They don´t give another taste or emit tanine or other substance.
-They are atached to the bottle, so you don´t lose it easily.

Take a look
http://forum.northernbrewer.com/viewtopic.php?f=9&t=68576

PP.