This bottle attachment was designed for regular 0.33L bottles. The adjustable inner tube allows the use with smaller bootles, too.
How it works:
Place the long end of the thin tube inside the bottle. Secure the attachment on top of the bottle neck.
Bring the attachment to your mouth, with the opening of the thin tube pointing away from you. Now 'down' the beverage - (Approximate time for a 0.33L bottle: 4 sec.)