TWSBI Precision Fix Pipe Mechanical Pencil - 0.7mm - Matt SilverWith over 20 years experience in making mechanical pencils, TWSBI knows how to make them to last. Constructed from all metal parts internally and externally and uses a super long built in eraser so you aren't replacing them often like in some other brands. The Fix Pipe mode has a fixed lead feed mechanism so the pencil is always ready to use at a moments notice. Great for drafting and using with a ruler. Lead size 0. 7mm