This sharpener has earned all its five star reviews. I thought they were kidding, or paid fake reviews. They're not. I've never seen anything sharpen like this--not even the heavy duty classroom sharpeners in the 70s! The points were razor sharp. You could kill someone with it. I'm not kidding. For this reason, and because sharpening it until the sharpener stops grinding (as the instructions others give) chews up HUGE amounts of the pencil, I usually just give the sharpener 4-5 turns, then stop and check the point. Most of the time, 5 is enough, depending on the pencil, and how dull it started out. As other stated, you don't need the clamp. Someone on Amazon gave a great review with directions (it comes with none, how stupid). It might have been on the the page for the green version of this sharpener. I'll give you my own quickie tips. 1. Pull metal face plate away from sharpener until it clicks into place. 2. Squeeze the two black knobs on the top together and hold while you insert pencil. 3. Insert pencil in until it stops. 4. Hold one hand flat on the top of the sharpener while you turn the handle with the other. 5. The sharpener will pull the pencil in as it sharpens, and you'll be able to hear/feel when the pencil is "done" (i.e. it is now a wooden stake capable of killing any vampire...except that it is now too short plunge in that deep) 6. If you don't want a vampire-killing pencil stub, then stop after 4-5 and check the tip, by squeezing the black knobs together again and pulling the pencil out. 6. If, after 4-5 rotations, the tip still needs a bit more sharpening, re-insert carefully and go another rotation or two, until you are satisfied. 7. Remove pencil again by squeezing black knobs together and pulling pencil out. 8. If faceplate is still sticking out, turn handle and it will retract 9. Empty the pull-out acrylic shavings drawer, or else the world's finest pencil shavings will end up falling out of the cracks and dusted across the room, no matter how careful you are. 10. Put it where your kids can't pick it up and throw it at each other, because I'm pretty sure someone is going to the hospital if this hits someone's head. 11. Hide any vampire-killing pencils from younger children or children/people who can't be trusted with stakes. p.s. This is fun to use. Too fun. I want to sharpen everything in the house. So do my kids. They are not allowed to use it, because they will make stakes of every pencil in the house, and I'm not buying new colored pencils each week. Let your kids use this at your own risk. Joking aside, I love this sharpener. It's so stupid to be this happy over a pencil sharpener, but when was the last time you bought something after 1980 that actually did an awesome job, and looked like it would last longer than a month? I bought it with much trepidation, because of the price, but the reviews convinced me it was worth it. I'm not sorry I spent $25 on this. Even though--ouch--that's a lot. Totally worth it, and better than constantly losing $2 cheapie manual sharpeners, or paying $12 (still a lot) and having one break. ETA: No vampires were harmed in the reviewing of this product. I tried, but the really-sharp pencils were too short. Okay, so maybe they were harmed a little. But they were just flesh wounds. UPDATE 6/26/16: Wow. This thing is a tank. Naturally, my husband let the kids all use it, because apparently he WANTS them to stab each other with deadly pencil weapons. Fortunately, they have refrained from doing so. They have also learned that if they sharpen them too much, their pencils disappear, and we'll run out too soon, so they have learned to stick to the 4-5 rotation rule. In the meantime, this sharpener has seen some major abuse. The little rubber foot pads are long gone, and it is scratched up a lot on the bottom. Sometimes the face plate wants to retract before I get the pencils in (no biggie, I just pull it back out again), and they've slightly bent one of the black handles on the top. However, despite the abuse heaped on this sharpener, plus the heavy use (my kids looooove drawing), it is still going strong. I have no doubt that no other pencil sharpener would have held up this well. And surprisingly, the plastic drawer has neither been lost, nor cracked. It stays in there pretty well, considering that nothing is holding it in. I still love this sharpener, and my only problem now is finding a little sharpener that I can take with me when I'm away from home. This thing spoils you.