Invisible Ink Pen, Daemson Spy Pen with 3 PCS Mini UV LED Keychain Flashlight, Disappearing Ink Magic Pen with Black Light Markers for Secret Notes, Fit for Christmas Halloween Holiday Gifts (3 PCS) | Disappearing Ink Magic Pens with Black Light Markers for Secret Notes, Fit for Christmas Halloween Holiday Gifts (3 PCS)

I don't really see a difference between the blue and yellow under the UV light (probably because it's blue) but the pink is very pronounced. Tried it on paper and faux leather so far and it takes a second to fade, but it isn't visible after it dries. On the paper, the pink marker left a very slight impression that you would not be able to see at a glance but if you look hard and know exactly where it is, you can see a small color difference. Haven't tested on other surfaces but so far, so good.

This is so cool! We used for a DIY escape room and it worked great! The kids loved it

These are very fun for the price. I got them for a treasure hunt puzzle game with a group of children. The lights aren't very bright, but I was pleased that I got several for the price (and I already have a UV flashlight so it wasn't a huge loss that they aren't the best). The markers were all full of ink--none were dry. They show up nicely under the lights, especially the pink. My biggest complaint is the blue appears to be pretty much identical to the yellow? At first I thought maybe there was a mistake and the blue marker got filled with yellow ink when they were made, but the blue pen is also the most visible pen under natural lighting, so it seems to be different. All of them are a bit visible until they dry, but if you look closely you can still sort of see the blue marks hours later. I may have gotten a bad one. The other pens are great though! I definitely recommend these (especially if others are getting better blue markers), they're lots of fun.

Bought this for my 7 year old granddaughter. She loved it and immediately wrote on her hand with the pen and shined the light on it to see her handwriting. The packaged came with 3 pens so she was going to give one to her friend. Great gift idea for kids and easy to use. She had fun with the pen.

We did a scavenger hunt and this worked marvelously! We absolutely loved the invisible ink - it showed up so well! Pros: - The pens work great - The lights actually show the invisible ink. - That are durable and last well - They are just so fun!!! Cons: - The marker tips are on the thicker side so writing small is not an option. - The ink does run if it gets moist or wet. This is a great price for the awesome item you get - I would highly recommend purchasing it!