Opticz UV Blacklight Reactive Large Tip Invisible Ink Marker, Red

This item is going when you want to find out how often your sheets are changed, I loved it, it is easy to dry, visibility is 0, and easy to use

It's hard to find a marker that visibly glows under blacklight. This one worked well enough though Color quality: great

This marker works well, but it does show up, without UV light, so be discrete in how you mark property, and they might not notice. The markings appear to be glossy, without UV light.

Opticz UV Blacklight Reactive Large Tip Invisible Ink Marker, Red, shows up well in the UV light. I wrote a clue onto a paper with this marker and then laminated the paper. The marker showed up just as well after laminating! Also available in other colors.

Just what I needed. It is invisible in normal daylight and really bright red when I shine the 30 watt UV flashlight on it.

This was purchased to place some invisible mark on my items before to sell them, to avoid those "return scams". Unfortunately, I found out that not only the writing isn't really invisible, but you could still see it under a regular light source, but the irony was that this is an UV pen that will fade away slowly when exposed under UV light. Otherwise it's fun to use as long as it last.

I was hosting an event and I wanted to have a game where a black light was needed to reveal clues on various envelopes. I was able to use this and it worked perfectly. Once the envelopes dried you couldn't see anything without the black light. It was perfect.

The tip on this pen is way too soft, needed to use as a marking device for equipment, but the tip didn’t hold shape and anything you try and write ends up just a huge mess and unreadable.

This pen is excellent, super bright and having it in pen form makes it so much easier to work with. A+++

Little bit expensive but awesome marker, lots of ink. Only thing is if you write across ink (pen or printed) it can leach into the tip of the marker and what you write on white surfaces can then leave a mark so it doesn’t dry invisible :( hence ordering a 2nd :)

Leaked all over my hand and felt like burns!!!!