Tombow's Graph mechanical pencil feels good in the hand and looks great. The 4mm long guide pipe supports high precision writing and its shake knock mechanism allows you to advance lead without losing your grip. Just shake the pencil while holding it.
The pen clip on the side can also be pushed down to do the same. A lead lock prevents lead extension by accident.
Tombow's most popular MONO eraser is attached at the top of the pencil's twist-telescoping mechanism, providing greatly improved erasing performance.
Add on the eraser refill pack and you'll be set for study.