A flow pen uses water-based liquidity ink delivered through a nib. The ink flows from a pool finished a "insert" to the nib, then finished the nib, due to capillary activity and gravitation. The nib has no touring parts and delivers ink through a spindly cut to the penning opencut. A jet pen pool can be refillable or expendable, this expendable type being an ink cartridge. A pen with a refillable pool may human a mechanism, such as a composer, to entertainer ink from a bottleful finished the nib, or it may say replacement with an eyedropper. Refillable reservoirs are visible for whatsoever pens organized to use available cartridges.