Description The TWSBI GO in Smoke is even more affordable than the TWSBI ECO fountain pen, and possibly more fun! The spring-loaded piston makes for one handed filling. This entry level TWSBI fountain pen has a transparent gray body and clear grip section, a steel nib, and has a clipless snap-cap. To fill your pen with bottled ink, simply unscrew the barrel from the section to access the mechanism, insert the nib into the ink, press down on the piston to compress the spring, and release! Screw the barrel back onto the section and you are ready to write!The TWSBI GO piston ink-filling system uses only bottled ink and the clear body allows the user to view the level of ink remaining in the pen at all times.