It is a friction ball knock of the popular character "Sumiko Gurashi" of San-x, When you knock, the color of the transparent relaxing part will change Friction ink which makes the ink colorless by temperature change is installed.
The frictional heat generated by rubbing with the rubber for erasing at the rear of the body turns the color of the ink into colorless, and you can erase the handwriting. As when erasing with an eraser it does not erase, there are almost no erasures left.
Size: about H146 × 11mm / water-based ink
Size pen : 0.5 mm