Opticz Blacklight Reactive Invisible Blue Ink Industrial UV Marker

Works great, can't see a think unless under black light, easy to use

I used this on metal surface and it applied and stayed on very well. Worth the money.

This marker does not work well on paper, works fine on plastic and cardboard.

This item enables us to covertly ensure a client who is claiming to have received unusable product too frequently is actually being honest and not defrauding us or our supplier

Very thick tip makes it hard to write anything clear. It’s really bright initially but the brightness under UV faded more than I expected it to and although it does remain visible it remains a far cry from very clearly standing out.

First off, the description of "it will be permanent on just about anything" is totally false. This "ink" easily rubs of after drying on anything but paper. The "ink" once dry on paper has little to no UV glow under the proper lighting as well. What a waste of money. I will return if possible. Hate leaving bad reviews, but this product is not as advertised. Buyer beware!

Works great with Infray UV light. Opticz is bottom in pic.

Just received this. I wrote with it on white paper and it worked just fine. **Only thing to consider when I used a different UV pen on colored paper, my "invisible" ink showed up a little bit. Consider than when you're writing on paper.