What distinguishes the P'3150 series is the combination of unusual materials. The basic element is a cylindrical barrel made of stainless steel that is painstakingly brushed. A characteristic of this series is the leather-coated shell that encases the barrel. The leather shell is made from the only the finest calfskin. An Elaborate tanning process renders it stable, tough, and and the same time, smooth and supple. The mechanical pencil is fitted with a tough 0.7-mm polymer lead, grade B and has a twist function.