invisible pen colorless fluorescent marker pen uv display marking pen secret writing pen

816 Invisible pen with cash detection and writing functions. The text disappears after writing with this pen for twenty seconds; it can be seen again after being exposed to a UV light. The ink dries immediately once written, and the marks become invisible at the same time. The pen has printed patterns on it, and there are various product designs available. 1008 cards per piece. Card-suction packaging. Sold worldwide, with stable quality and reasonable prices.