A magic pen for fun writing secret messages with invisible ink. The messages are then revealed under the UV light. It's magic! An invisible ink appears in the beam of the UV torch hidden in the lid. It has an On/Off button. It functions with 3 LR44 HD batteries that are included. Size of the pen: 13 x 0.5 cm. Suitable from 8 years. Warning! This is not a toy! Not suitable for children under three years, choking hazard due to small parts.