The modern Wenger corkscrew compares well to stand-along corkscrews. It is sharp, penetrates well, and grips the cork tightly when you are extracting it from the bottle.
Uses: For best results, insert the corkscrew in as far as it will go (just leave yourself a little room so you can still get your fingers around the knife). Then grip the knife tightly with one hand, hold the bottle tightly with the other hand, and pull.
The corkscrew is also helpful for other tasks, including: