What pen is used to check rice paper? It can disappear.

Red gel pen. After checking the rice paper, the pen is red and neutral. This kind of pen is usually made of a special ink, which can disappear within a certain period of time, leaving no trace. The use of this pen is very suitable for scenes that need to temporarily record some information, make some drafts, or temporarily mark something, such as sketching, marking on paper, or filling out some forms.