Sporting an ultra-slim diameter of 3.7 mm, OHTO's Minimo pen is the world's thinnest ballpoint pen (at the time of release). It comes in a holder consisting of a flexible plastic card with a pen sleeve attached. Convenience is key with this pen. The retractable mechanism allows easy one-handed operation, and the holder card makes the pen very portable. Slip it into your daily planner, pocket notebook, or wallet. The card (not including the pen sleeve) is the size of a Japanese business card (3.6 x 2.2 inches, or 9.1 x 5.5 cm), which is a little larger than credit cards and standard U.S. business cards. The pen can be stowed on its own if desired, using the clip to secure it to papers and pockets. The pen writes well, with smooth black ink and a needle point tip that is convenient for jotting neat, small memos.

Black ink is included and is refillable.

Note: When replacing the refill, do not throw away the spring and metal stopper from the original refill. Remove the original refill from the metal stopper and slide the spring off. Insert the new refill into the metal stopper and slide the spring over the refill. Then you can insert the new refill into the pen.