This item is an outer barrel for a customisable multi-function pen. Inner unit is sold separately. This item can only be used with an inner unit from the "Uni Style Fit" series. You can mix and match by combining any of the outer barrels (single colour, 3-colour or 5-colour) and inner units (gel ink, ballpoint, mechanical pencil). Ballpoint Pen Barrel 3-Colour/With Grip 1.52x1.2x14.62cm Uni Style Fit Series