When is a nut tool more than just a nut tool? When it is a Trango Shark Nut tool with locking knife.
Joking apart, this is a really clever design. The Trango Shark is a beautifully manufactured piece of kit constructed from surgical quality 440-C stainless. The super-sharp serrated knife can easily be swung out from the handle end of the Shark with one hand, and is ideal for trimming anchor tat. However, the Shark is designed in such a way that it cannot be opened when clipped to a carabiner. Probably a good thing.
The Trango shark has an in built slide locking mechanism, which ensures it will stay open when you need it to be.
If you're the kind of climber that likes to watch his/her weight you'll probably be interested to know that the Shark weighs in at just 83g.