UV-Marker , Permanent, Bullet Tip, Clear

Not easy to get off plastics at all and can't see it after it dries and wears in a bit

To help mitigate bird strikes, I used these clear UV markers to draw a vertical pinstripe pattern on a series of windows in a bedroom (lines drawn at a narrow 2 1/2" spacing). 5 months later, it appears to be working - not a single strike (whereas previously I had a strike every month, at least). The clear stripes can be seen, but are not obvious. I applied the marker to the inside surface of my insulated windows. For bird's optimal visibility, I am reading that it is recommended to apply UV patterns to the outside surface of the window. I have not tried this yet. (I have concerns over the durability of the "permanent" marker being exposed to rain and snow, and am also concerned about dirt accumulating at the linework. But, next spring, I'll give it a try on the exterior to see how well it performs. Will keep you posted.)

These pens leave a UV mark that is very clear under UV light. The ink is transparent, however on certain materials it is not invisible and can discolor where it left marks. If you were hoping for an invisible marker, this won't do the trick. However it is very UV reactive and produces a bright white color when exposed to UV. Does have some fumes when using, so avoid small enclosed spaces.

A great idea but there is issues with the paint flowing to the tip of the marker and when it does it floods out as with all paint markers but this was exactly what I was looking for I haven't been able to utilize it before it's intended purpose yet though.

I use these for making UV markings on items exposed to the elements. The makings seem to hold up fairly well over time. Do they fade eventually? Yes, but not for several years. Pretty good compared to other markers I have used. They cost a bit more but in this case you get what you pay for.