Pen Type-A is precision machined out of solid metal. The body and sleeve of the pen are made out of stainless steel. Pen Type-A is available with an ultra-durable matte black ceramic-polymer coating (Cerakote). The ultra-high machining tolerances between the pen and sleeve create a piston-like effect. The pen falls slowly into its sleeve and makes a nice popping sound when you pull it out quickly. Pen Type-A ships with a 0.3mm Black Hi-Tec-C Ink Cartridge. REFILLS available as well. Made in the USA: Pen Type-A is manufactured at a multi-generation machine shop in Vermont. Each pen is inspected before it goes out, and if there is ever a manufacturing defect we will happily take it back to repair or replace. Refills: To replace the ink cartridge, simply unscrew the back of the pen with a coin. The cartridge in this pen is a Black Pilot Hi-Tec-C 0.3mm cartridge (REFILLS). Hi-Tec-C cartridges are available in 4 line widths and over 30 colors and are widely available in stationery stores in Asia and sold in the USA under the name G-Tec-C. Specifications Dimensions Pen/Sleeve Diameters: 9.8mm/12mm Pen/Sleeve Length: 125mm/120mm Material 300 and 400 series Stainless Steel