The SenseMatic automatic pencil senses when you need more lead and automatically advances just the right amount while you write. No clicking, no twisting and no sharpening. Pencil is disposable - non-refillable. Yellow barrel with 0.7mm lead. Packed 12 pencils to a box. NOTE: The black barrel with 0.5mm lead is no longer available and has been discontinued by Dixon. $9.75 Need more information? Please feel free to contact us at 1-800-592-6940 - Ask for Extension 488 or Internet Sales.