Faber Castell created the first pencil of its kind in the world (lead holder/clutch pencil). This particular one is the most improved version of the successful TK9400, to which they simply added the sharpener and clip! I have almost all pencils of this kind, from all brands, and the TK4600 is by far the most reliable of all, by a long shot. Simply put, it is the best pencil in the world for freehand or technical drawing. Whether this one or the previous versions (same pencil, just designed for different purposes), it is the best option out there. Don't be deceived by its low price, or if you see others made of titanium, etc., this one here is the best. The TK9400, which started it all, comes in various versions and is also designed for freehand or technical drawing. The TK9500 is designed for cases like school/schools, etc., while this 4600 is made to be taken everywhere with you, which is why they added the sharpener to the button! Hence the detachable clip, so by easily twisting and pushing it upwards, you can remove it to make the pencil even more comfortable, making the TK4600 automatically the most flexible! You can use any brand's leads you want, as long as they are 2mm in thickness! If you want hardness, from 4B to 6B, then you should buy the Faber Castell TK9400 3.15mm, which is almost the same pencil, just a bit thicker, with a more comfortable grip (when holding it in writing position), and is designed for softer graphite 4B and 6B. A smart idea that only this company does. The others only produce them in 2mm thickness and besides the fact that their leads break easily, they are also not of good quality. So, I would recommend leads only from Faber Castell, as here in Greece, they are by far the best you will find. Only the UNI Mitsubishi leads are worth it, but you can only buy them online, from stores abroad.

;Extra guide, for the best mechanical pencils for every use: My favorite mechanical pencils (0.3mm - 0.9mm) and the best ones for drawing are the Pentel Graphgear 500 0.5mm and as a slightly cheaper option, the legendary Pentel P205 0.5mm. For writing and to carry it with you every day, if you want in 2mm leads, the best pencil for sketching and at the same time, the most flexible pencil of all time, is the Koh-I-Noor 5340 (5.6mm). What can one say about this pencil! Only the options in leads, and the fact that the same company produces the best Red Chalk (Sanguine) and Sepia, is enough! Just try it, those of you who are into sketching, and you will discover it, it is a fact and not just my personal opinion. If you want a mechanical pencil in 0.5mm/0.7mm, to carry it with you for writing/notes, then the best one is the Pentel Kerry with Pentel Ain Stein 2B leads, either in 0.7mm or 0.5mm, depending on your preferences!

P.S. These are a fact according to general consensus, the best mechanical pencils in the world and not just my personal opinion and experience. Having tried almost everything at a professional level, I have confirmed that mechanical pencils are one of the rare cases where the saying "you get what you pay for" doesn't apply perfectly. This is confirmed, as the best ones for drawing, almost always, are not the most expensive, but rather the mid-range priced pencils.