YM371W Specially designed ink disappearing ball pen. The characters will disappear in hour after writing， it disappears faster if there is water. It looks like a common ball pen by look， nobody recognize it is a magic pen Pen can be refilled again.   Package Details Weight: 38.52 g Size: 21*4.1*2.1 cm Package Includes 1 × Amazing Magic Ink Disappearing Ball Pen