Parabellum,
A swish device, but only required if you're female and / or drink wine. Being a heathen northerner, I prefer to go for beer or shorts. The obvious plus side of this is that a lot of decent beer comes in bottles rather than the usual pint of Carling you get in the Mess, which means you can carry a bottle between the 3rd and 4th fingers whilst carrying your plate of food, not to mention being able to slip a bottle in each of your trouser pockets.
Very handy when you are facing an imminent bar closure. Not sure how well it would go down with the Colonel 'at home' though.