This is a 375 Type B series Matthew Martin Tactical Click Pen in zirconium and matte carbon fiber. This tactical pen has a shaft of carbon fiber and titanium constructions with a 6Al4V titanium pocket clip. The pen accepts Fisher Space Pen refills that are commonly available at office supply stores. The rugged pen weights in at .7 oz and is extremely well built. The Length of the pen is 5 1/4". Made in the USA by Matthew Martin Pens. Model 375 CUCF type B. This pen features the Tuff-Writer all titanium click mechanism for strong, long lasting and reliable click action.