Lead Diameter
The thickness of the lead (writing rod) in a pencil or each crayon in a set (see "Product Type").
The meaning of this parameter depends on the specs of the pencil. So, in traditional pencils (lead in the casing), the thickness of the lead determines only the maximum thickness of the line that can be drawn in one pass. In collet models (see above), this parameter is also necessary to search for refill leads: their diameter must correspond to the size of the lead slot of the collet. And interchangeable leads with a diameter of more than 2 mm, usually, also have to be sharpened. However, anyway, each size is good for its tasks: thin leads are convenient for precise small work, and for large volumes of shading, it is desirable to have thicker pencils — they are not only more convenient, but also do not expend so fast.
As for the crayons, their thickness primarily determines the ease of use, as well as compatibility with special collet pencils that play the role of holders.
Lead Length
In most cases, lead length actually refers to the length of the pencil or crayon itself (see "Product Type"). This allows, to a certain extent, to assess both the dimensions and how long the lead will be in use. In collet pencils (see above), this parameter is indicated very rarely — usually, for models for graphite lead thicker than 1 mm. If it is specified, it usually refers to the regular size of the leads produced for this pencil, or the maximum length of the lead that can fit the pencil.
Sharpener
A sharpener is included to the package with the pencil. Sharpeners can be designed for the pencils themselves (in common models), for refill leads (in "collets", see above), and for crayons. Anyway, use of such sharpeners is much more convenient and safer than knives or other improvised devices.
Clip
The presence of a
clip in the design of the pencil.
The clip has the form of a narrow elastic plate, designed primarily to secure the pencil to thin objects — for example, the cover of a notebook or the edge of a pocket. In addition, if the pencil is round, such a device does not allow it to roll. Most models with this feature are collet pencils (see above), but there are exceptions — traditional pencils, supplemented with clip-on caps.
