A pack of 10 x 8g nitrogen cylinders. Each cylinder contains 8 grams of gas and can be used with a variety of kegs fitted with the correct holder.
Adding nitrogen to your beers gives a much smoother creamier head - thinks Guinness or Cafreys.
Dimensions = 2 1/2 long and 3/4 in diameter.
They can also be used in Sodasyphons.