Top quality, possibly the best product this company produces. I also have the equivalent from M+R, because it can do more, but even though it's German, it doesn't match the quality of this one. The filters are for cleaning the nose after sharpening and removing the graphite dust (don't forget, it's for sharpening pencil tips used for technical drawing, so the filter is necessary!). Personally, I put a drop of oil (either s;inger or Ballistol) on the axis that the lid presses on and rotates! Just lift it, it comes off easily without even clicking, so you can easily empty it and prevent clogging! The graphite it holds is perfect for those who do freehand drawing, so it's another big advantage of this sharpener!

PS If you use these types of pencils a lot, other sharpeners I would recommend are the Faber Castell TK 18 66 00 (2mm & 3.2mm), the KUM Longpoint Automatic, which sharpens both wooden and 2mm & 3.2mm tips!! Also, the tiny M+R 2mm sharpener, which is yellow and the best small sharpener on the market for 2mm tips (even better than its equivalent from Faber Castell or KUM).

PS2 The secret to sharpening is not to overdo it! If the tip is sharpened too much, it will break easily and you'll have to start over! So, ALWAYS sharpen with frequent breaks to check the tip and make half rotations or even less, depending on whether you're getting close to the desired result or not! The more careful you are, the better the result. If you rush and do it forcefully, any sharpener will either break the tip inside or break as soon as you use the pencil, because you've made it thinner than it should be!! Remember these tips, they are more important than the sharpener itself!

PS3 If the sharpener frequently breaks tips while you're using it correctly, then it needs to be replaced (or sharpened for those who know) the blade of it