Spare brass tubes for Slimline and Comfort style pen and pencil woodturning project kits from Penn State Industries (10) pre-scuffed tubes per pack; Enough to make (5) dual tube pens and/or pencils Each tube has a 7 millimeter outer diameter Each tube is 2-1/32" long Use to replace damaged tubes, or to work ahead on your project Spare brass tubes for Slimline and Comfort style pen and pencil woodturning project kits from Penn State Industries. (10) pre-scuffed tubes per pack; Enough to make (5) dual tube pens and/or pencils. Each tube has a 7 millimeter outer diameter. Each tube is 2-1/32" long. Use to replace damaged tubes, or to work ahead on your project.