A writing instrument, in particular a pen, comprising at least two reservoirs for storing colorants or inks of at least two different colors, characterized by at least one pumping means which is designed to be actuated by at least one finger of a user.

A writing instrument, in particular a pen, comprising at least two reservoirs for storing colorants or inks of at least two different colors, characterized by at least one pumping means which is designed to be actuated by at least one finger of a user.

A writing instrument, in particular a pen, comprising at least two reservoirs for storing colorants or inks of at least two different colors, characterized by at least one pumping means which is designed to be actuated by at least one finger of a user.

A writing instrument, in particular a pen, comprising at least two reservoirs for storing colorants or inks of at least two different colors, characterized by at least one pumping means which is designed to be actuated by at least one finger of a user.

A writing felt pen including a barrel and a nib attached to the barrel, and a deformable pouch comprising a mix of absorbent polymer and fibres, an ink being absorbed in the absorbent polymer and the nib being in fluidic communication with the mix.

A refill for a writing felt pen, the refill comprising a deformable pouch and a nib inserted into the deformable pouch, the deformable pouch comprising a mix of dry absorbent polymer, fibers and dry ink.

A refill for a writing felt pen, the refill comprising a deformable pouch and a nib inserted into the deformable pouch, the deformable pouch comprising a mix of dry absorbent polymer, fibers and dry ink.

A compensation membrane and a pen or the equivalent including a compensation membrane. The compensation membrane being configured for compensating a pressure difference between the outside and the inside of a free ink reservoir of a pen or the equivalent. The membrane including a first portion having a first rigidity and a second portion having a second rigidity, the first rigidity being less than the second rigidity.

A compensation membrane and a pen or the equivalent including a compensation membrane. The compensation membrane being configured for compensating a pressure difference between the outside and the inside of a free ink reservoir of a pen or the equivalent. The membrane including a first portion having a first rigidity and a second portion having a second rigidity, the first rigidity being less than the second rigidity.

A refill for a writing felt pen, the refill comprising a deformable pouch and a nib inserted into the deformable pouch, the deformable pouch comprising a mix of dry absorbent polymer, fibers and dry ink.