The Private Reserve ∞ Infinity Fountain Pen Ink with the E.C.O (extended cap off) Formula is available in a variety of colors. This is the Red color, and it comes in a 60mL luxury ink bottle. Yair Greenberg, the owner of Private Reserve Inks, is proud to announce a break-through in fountain pen ink technology and truly, a game changer for the fountain pen industry. For many years, they were trying to come up with a new ink formula which will allow a fountain pen user to leave the pen capless for a long period of time. Until now, to write with a fountain pen often to avoid the ink from evaporating, drying and clogging feeding system.