NEW FORMULA - STEIN has an internal ‘honeycomb’ structure. This ceramic frame holds the leads firmly from the inside.And it makes the leads Super Strong.STEIN leads have a strength of 130g (0.5mm HB)*Average value, 10% STRONGER than our existing refill leads.STEIN also provides a smooth writing feel.Less debris on paper or your hand when you touch it.Suitable for drafting, sketching and general writing.