Dykem Permanent Industrial Marker, Ink-Based, Clears Color Family, Medium Tip, 1 EA 91195-1 - 1 Each

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.)

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

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.

It works well.

If you buy this marker and you get a NEW one then it is the best. It has a thick line, it draws on plastic/clear acrylic easily and dries immediately and permanently. I love this marker. The first one I bought was great and I got a lot of use out of it. I then purchased 4 more and they all arrived either USED/or OLD BECAUSE they were all dried up.

I work in an large mechanical repair facility and we have used these types of pens for years. This is the first time I have tried this brand. The liquid leaves a shiny residue so it is not clear (not a huge deal) and does not glow under numerous uv lights that I have tried. I have high quality uv lights at my disposal (because of where I work) but none make the marks illuminate to even a small degree on any surface that I have tried Additionally the marker simply drips the marking liquid out when you attempt to use it. In fact the cap is filled with the liquid when opened. I assume the pen is faulty and maybe that is why the fluid is no good. Anyway, waste of 13 bucks.

Tools, electronics, it does it all. Will update with acclimate weather test on metal tools.

I got this in a huge box, inside the box was a bunch of paper and the marker in a ziplock baggy...The cap was off the marker in the bag, and when I put it ON the marker, it would just fall off if I bumped the marker with my finger or shook it.So I used a piece of heat shrink tubing on the cap to put it on the cap, (while the cap was off the marker) This fixed the problem of the cap falling off.I got the ink flowing to the tip of the marker, but it just... pees out of the marker while writing if any pressure is applied at ALL to the tip so you have to write VERY gentle with it, and if you push the tip IN, it squirts fluid forward out of the tip.The felt nib falls out of the marker often, when I pick it off the surface to write another letter, it slips forward, and if I pick it up too fast, it just, falls out of the marker...I may have just gotten a crappy marker, but my hands are covered in this UV ink, and it leaked all over the items I was marking with it.... Like it just pissed all over the place basically.Now I don't know if it's just my luck, and I happened to get a crappy one, or if this is just, how they are.Either way, I am not pleased with it.HOWEVER, what id DID write was barely visible in normal light... a bit light blue hue to the PUDDLES it pissed out though.