Messograf Caliper Pen
Caliper rule? Tire tread gauge? Ruler? Thread scale? Writing instrument? The Messograf is all of these. It is a multipurpose instrument, constructed of chromium-plated brass for those who demand more than just the joy of writing. Many have tried to copy it - none have succeeded. This is the original. Retractable ballpoint pen with large capacity cartridge. Recently featured in ToolMonger Blog: http://toolmonger.com/2009/08/03/always-have-calipers-on-hand/