Yes, DanceSafe, and most exchanges in the US are stocking or trying to stcok this newer item:
$20 for 10 one use strips, free shipping (USA maybe CN too):
https://dancesafe.org/product/fentanyl-test-strips-pack-of-10-free-shipping/
A line is a line - if you can see it - as I wrote in a post above the company that developed this test has made damn certain that it is accurate and precise.
If you see no line, white as the area below and above the control line (the one that is always there - or the test is invalid!) DO NOT USE THE SUBSTANCE!
No lines - neither - it's a bad test. Use a new strip and re-read the directions. You have time to test every shot. If you snort a drop of water in the empty bag on the residue you're dosing from - that will be a pretty valid test, not as accurate as testing the left over residue from a shot as that is very well mixed.
Testing anything other than the residue from prep'ing an IM/IV shot - imo is not gong to be an accurat test.
If you do not shoot the dope that you test - please read the above link thoroughly for their info on testing materials you don't intend to inject.
If anyone needs more info on where to get these strips or absolutely cannot get them in the US - PM me. Particularly if you've been posting to my threads from the last few weeks while I too have struggled with fent in my dope.
Please - even if you have used these strips many times before read the dancesafe.org link above.
Mods ^^ if helping people with HR testing strip info / obtaining them is a violation, I'll take it and you can please delete this post. I'm trying to help a few of the most desperate out there.