Strength & Deep & Smooth -Uni-ball Extra Fine Diamond Infused Pencil Leads, 0.5mm-hb-[nano Dia]40 Leads X 3 Pack/total 120 Leads
Uni Nano-Dia is the very latest in pencil lead technology. 400 million 'nano-diamonds' per lead improve smoothness and strength and high viscosity oils improve smoothness and darkness.