The official, patented name for the little plastic Ping-Pong ball contained in pint cans of Guinness and some other beers from the UK. Some people call it a widget.

This device is responsible for the extra-creamy head produced by these cans. Apparently the taps used to pour the beers (Guinness, at least) add nitrogen to the mixture, which is what the Smoothifier seeks to recreate. According to the patent text, here is how the device works its magic:

The key to the texture of the beer as delivered on tap, or in the special can, lies in the fact that the bubbles produced by nitrogen are much smaller than CO2 bubbles (like in Budweiser), so the head contains more beer and less gas. The popularity of the widget can is also assured by people like me, whose enjoyment of the beer itself is only heightened by our geekly fascination with the ingenious delivery system.

Credits:The bulk of this information is also found in this writeup by bozon. The original info is from the Unofficial Guinness FAQ and Folklore Page at The patent, held by Arthur Guinness, Son & Co., is number 4,832,968 in the database at