I am not familiar with the mechanism, but it is perfectly working.

We coppied following from an other ebay listing: 

Push the button to extend the pencil. Twist after extended to change the lead color. Turn the top metal knob to advance the leads. The leads diameter and grade are not known. The material the pencil is made of is not known.

High quality, made in USA.

When looking for other collectible pens, or for daily use,

just visit my shop.