I have two that I particularly like: the one on my pen knife, and the sort that's like a little man whose arms go up as you screw it into the cork. I feel like a wuss when I use it, but it does work. Don't get the sort that claim to do everything for you, so you don't even have to screw anything anywhere; countertony's father had one, and half the time it just pushes the cork straight into the bottle.