Pentel Ain Stein C287 0.7mm lead. This new improved Pentel Ain formula utilizes a molecular ceramic frame to support the graphite and lubrication particles, greatly improving strength and break-resistance while continuing to provide superior smoothness and darkness. Pack of 40 0.7mm x 60mm leads suitable for all 0.7mm mechanical pencils. About 10% stronger than any other Pentel refill lead thanks to a ceramic cell structure. Supplied in easy to dispense tubes. Smoother than other refill leads on the market. Suitable for all 0.7mm mechanical pencils. HB grade lead.