Color: 3 color set The friction ball of knock type can be used speedily to write a notebook and materials. Knock is done with a clip, the knocking surface is large, it is easy to knock shape. Knock indicator: By color appearing from a small window “ON” You know the progeny. 3 color set. Ink color is black, red, blue, three colors. The pen point is 0.7 mm. ?Friction rubbing and disappearing? POINT 1: The ink is transparent when rubbed. POINT 2: Even after scrubbing, it is not erasable. POINT 3: It is possible to write / erase any number of times. ?Friction ink mechanism? Special microcapsules play a role of pigment for friction ink. The combination of the three kinds of components contained in the capsule changes due to frictional heat, and the ink becomes transparent. ?? attention? Please do not use for certificates, address names etc. Do not disappear. · Do not place the product in a place exposed to direct sunlight or high temperature. When it reaches 60 ? or higher, the ink becomes colorless. · When the temperature reaches around -10 ° C, erased handwriting may return. · Please do not use for writing other than paper. Depending on the type of paper such as thermal paper and the characteristics of the printed matter, it may be unsuitable for erasing. · Rubber for erasing rubs with dirt attached, the paper surface becomes dirty. Please use it after removing dirt such as wiping off. · It can not be used for mark sheet.