4.29” overall. Rectangular shape for writing comfort. 6mm low-profile body. Embedded micro socket provides a no hassle refill replacement that does not require tools. Compatible with common D1 ”multi-pen” (TEC02, TEC03), Fisher Space Pen, and Rite in the Rain (RITR37R) refills. No possibility of accidental ink retraction during use. Anti-roll design. Assembled from 24 individual, custom machined components. Black aluminum body with stainless guide rails. Boxed.