Invisible Ink Pens, 5-Pack

Planning a treasure hunt or a detective game? These invisible ink pens add a reveal to written clues without needing a separate light, since each pen has a built-in UV light in its cap.

Write a message on a sticky note or paper, wait a few seconds, then shine the cap’s light over it to reveal what you wrote.

The pack contains five pens in random colours, so the set suits party bags or a group activity where each child can have one.

How to use it

Use the pen to write a clue, secret note or message on a surface, then give the ink a few seconds before revealing it with the light built into the cap. For a home treasure hunt, you could leave a hidden instruction on a sticky note and let players scan it when they reach the right spot. The reveal is part of the activity, unlike an ordinary pen, the message is intended to stay hidden until the light is used.

The listing says the ink works on paper, T-shirts, skin and other surfaces, and describes it as washable. That broad claim may be useful for craft or party play, but there are no cleaning instructions or details about how it behaves on different materials. If you want to use it on clothing or skin, try a small, discreet area first rather than assuming every surface will clean up the same way. What makes a clue more fun than seeing it appear only when players find the right tool?

Pros

The built-in UV lights mean there is no separate torch to hand around, and batteries are included and installed. Each pen has a pull tab intended to help preserve battery life before use. Five pens also make this a more practical party favour than buying a single novelty pen, particularly for a group activity or classroom game.

The main limitation is that the pen colours are random, so you cannot choose a matching set. The listing also gives no details about ink volume, light specifications or how long the batteries last. Treat it as a simple game accessory, not as a substitute for a more elaborate detective kit with extra props or detailed game materials.

Spec sheet

• Type: Invisible ink pens with built-in UV lights
• Pack: Five pens
• Colour: Random colours
• Ink: Described as washable and disappearing
• Batteries: Included and installed, pull tabs are fitted
• Age guidance: Children over three, the listing warns about small items

What I’d decide

Makes sense if you want a low-fuss way to add hidden clues to a birthday party, classroom activity or treasure hunt: write the message in advance, then let the players reveal it with the cap light. Compared with visible clues written using an ordinary pen, this set gives the activity a simple spy-game twist without requiring a separate UV light.

Not for you if you need specific pen colours, detailed battery or light information, or dependable cleaning guidance for a particular fabric or surface. The listing calls the ink both permanent and washable, so its cleanup behaviour is not entirely clear. Based on the listing, the strongest reason to choose this set is the five-pen format with built-in lights, for children, keep the small-item warning and age guidance in mind.