Looks like a regular key - Opens bottles.

The best bottle opener is the one that's always in your pocket. Impress your mates while drinking al fresco: Open bottles with your keys... Or what at first glance looks like a standard door key, but on close inspection the action end is actually a bottle opener. If you always forget to bring a bottle opener to the picnic, now you'll never leave home without, unless of course you forget your keys. A modern design classic in its own lifetime! Compact, subtle and incredibly useful.