writing instruments 
The first true writing instruments were made by the Sumerians in Mesopotamia nearly 5,000 years ago.
Instrument invented at the beginning of the 20th century; the writing tip holds a small rotating ball.
Tip that contains the ball bearing used to deposit ink from the cartridge onto the writing surface.
Curved metal bar that attaches the ballpoint pen to a pocket.
Elastic metal part that compresses to push the refill out and relaxes to retract it.
Part that is activated by the push-button; it pushes out or retracts the writing tip when pressure is applied.
Protruding part that locks the thrust tube in a forward or retracted position.
Small reservoir containing ink and ending in a point.