Steel case with 3.5cm diameter, screw cap ensure water is not easy to spill out. The cap also with plastic plate inside perform as gaskep to avoid water seepage.
With metal clip can either clip onto the drawing paper or stack on a magnetified drawing pad. 
 
金屬外殼, 可以夾在畫紙上, 或附在磁鐵板上. 
蓋子內有塑膠墊片, 更緊密的封蓋以附止漏水
尺寸 3.5cm 直徑。