The Quicker-Clicker is both convenient and comfortable, everything you want in a mechanical pencil! The distinctive, Quick-Clicker side action button allows you to advance the lead without interrupting your flow. Details:Transparent black barrel Fits 0.5 mm leadEquipped with a sturdy metal clipLarge replaceable eraserThe original side advance mechanical pencilConvenient side button propels lead for continuous writing without changing hand positionBrass clutch guarantees consistent lead advance every timeTransparent barrel allows user to monitor lead supplyRefillable with Pentel Super Hi-Polymer® Lead (sold separately)