Makes erasing a breeze. Turn on the eraser and let it do the erasing for you. Black plastic ergonomic body (118mm L x 24mm W x 20mm H) with a removable metal clamp theat holds a white eraser. Inlcudes 30 replacement erasers. Battery operated (batteries not included) - 2 x AAA batteries required. Erasers are standard international size (5mm x 25mm) - refills are available at most major stationery stores.