Large Invisible Ink Marker,Medium Tip 2MM Water Based Invisible Securitas Uv Pen for Paper,Skin,Wood,Leather,Plastic,Cloth,Ceramics, Glass, Metal - Pack of 2

Works well. Picture quality isn’t great but don’t let they dissuade you. This works well

Diwimiki Large Invisible Ink Marker,Medium Tip 2MM Water Based Invisible Securitas Uv Pen for Paper,Skin,Wood,Leather,Plastic,Cloth,Ceramics, Glass, Metal - Pack of 2very cool. hard to say how the writing holds up over time or to the elements or abuse, and whether the glowy bits still be glowy. but on test use with a filtered uv light they look bright and clear a bluish cyan kind of tint, kind of like glow in the dark blue. on paper it is 99% invisible. on an aluminum coffee mug you can see the writing as a different sheen. but you have to be looking for it. mostly invisible, but the writing is a different sheen under normal light. still pretty cool, but not as spyops as one may require.