Handheld implement in particular writing instrument

A handheld implement comprising:

• a shaft that has at least two shaft parts (1) that are releasably connectable together via a plug-in coupling (2) that has a coupling unit (3) at each front end of the shaft parts (1),
• each coupling unit (3) of the shaft parts (1) comprises:
• a slide (4) that is held immovably in a guide hole (5) open on a face side in an associated one of the shaft parts (1) and protrudes beyond the guide hole (5) with a slide portion (6),
• the slide portion (6) including a free end formed as a latching fork that has a latching opening (9) between two fork arms (7, 8),
• the slide portion (6) bears a latching protrusion (10) on an inner side thereof behind the latching fork in a sliding direction,
• a guide sleeve (11) that encloses the slide (4) and is guided movably in the guide hole (5) counter to the restoring force of a spring-or rubber-elastic restoring element (12), and
• wherein, when the front ends, having the coupling units (3), of two shaft parts (1) are pressed together, the latching fork of one of the coupling units (3) is latchable on the latching protrusion (10) of the other of the coupling units (3) with at least one of the guide sleeves (11) being pushed back.