The official name for this tool is a Microplane Rasp Grater. It’s a little tool with a big name, but it deserves the title. If you cook at all and don’t have one, get one. I use one of these daily, they’re always in the dishwasher.
They effortlessly grate fresh garlic, ginger, hard cheeses and are fantastic for lemon, lime and orange zest— you get the zest with none of the pith. Over the years I have acquired four different models, but two models are my favorite. Funny, I use them all the time, yet hardly ever for cheese.
My first favorite doesn’t have a grip (check it out at Sur La Table) and is the best for zest, because the holes are so small, which means less pith in your dish (say that five times fast).
The rasp grater with a handle (you can find one at William Sonoma) is handy for grating garlic and ginger (cheese too). When you grate ginger you don’t even need to peel it first, just wash and grate away.