Uni Nano Dia is the very latest in pencil lead technology, resulting in better break-resistance than you would usually find in a coloured lead. 400 million 'nano diamonds' per lead improve smoothness and strength, and high-viscosity oils give a high degree of colour lay-down. Erases easily with a standard pencil eraser.

The pack of 20 leads are 0.5mm in diameter and 60mm in length.