Invisible Ink Pen allows one to write the secret message on the note, and the key to "unlock" the words is the cap of the pen, there is a special light which allows the secret words to show themselves.

Packing: Each on blister card,

50 pcs/inner box, 500 pcs/carton,

M.: 55.6 x 31.1 x 57.8 cm (3.53 cuft)

G.W.: 12.4 kgs, N.W.: 9.8 kgs