PROPELLING PENCILS

1.  The classical retractable pencil

The pressure on the mechanism is exerted by a rotational motion. 

2.  The propelling pencil with a continuously rotational mechanism

This mechanism is actIvated to retract or advance the lead by twisting the barrel counterclockwise or clockwise.

The lead used is either a thicker, "conventional" pencil lead or a polymer lead.

It is better not to charge the lead holder with more than 3 refills. That way, they cannot get wedged or jammed.