A 10B pencil, often referred to as a 10B sketch pencil, is an extremely soft and dark drawing pencil. The "B" designation in pencil grades stands for "black," indicating the softness of the lead and its ability to produce rich, dark marks. The higher the number before the "B," the softer and darker the pencil lead.

A 10B sketch pencil is favored by artists for its ability to create deep, velvety black lines and intense, smooth shading. It allows for a wide range of tonal values, making it a versatile tool for artists who seek to achieve dramatic contrasts and highly detailed work in their drawings and sketches.

The softness of a 10B pencil makes it well-suited for expressive and emotive drawing styles, as well as for creating subtle gradients and smooth transitions between light and shadow. Artists often use 10B pencils for figure drawing, portraits, and other subjects where capturing intricate details and nuanced shading is important.

It's worth noting that due to the extreme softness of the lead, 10B pencils may require more frequent sharpening and can be more prone to smudging compared to harder pencils. However, for artists seeking the darkest and most expressive drawing capabilities, the 10B sketch pencil can be an invaluable addition to their artistic toolkit.