And the paper mate has a great eraser, as does the Pentel Twist Erase

The perfect mechanical pencil would be the writing end of the Kuru Toga, and the click/eraser end of the Pentel Twist-Erase III

My favorite mechanical pencil is still a Pentel Twist-Erase III, like this Pentel Twist-Erase III Automatic Pencil with 2 Eraser Refills, 0.7mm, Assorted Barrels, 2 Pack (QE517BP2-K6)

My favorite mechanical pencil is still a Pentel Twist-Erase III, like this Pentel Twist-Erase III Automatic Pencil with 2 Eraser Refills, 0.7mm, Assorted Barrels, 2 Pack (QE517BP2-K6)

, Zebra Del Guard 0.7, Pentel Twist-Erase