Pay no attention to numbers such as 3W or 5W or 10W. They are often meaningless or made up, and don’t correlate to actual performance. Only measurements from trusted reviewers who state what they are measuring and compare different flashlights using the same setup are meaningful.
No matter what you get, you must take precautions to avoid injuring yourself and others. These are powerful enough to cause harm if misused. Never look directly into the flashlight. Avoid pointing the flashlight at surfaces which reflect light back at you. Use polycarbonate safety glasses which filter UV light.
Convoy is the gold standard in UV flashlights. By the way, your Convoy link is not from the official Convoy store on AE.
There are 3 models, but those with filter cannot ship to the US due to patent issues. I have the Nichia model and I recommend it. LG models emit a lot more visible light without a filter, which is why they are sold with a filter. Nichia is pretty good even without a filter. You can get a ZWB2 filter for it if you want, but you won’t need it for charging GITD powder pigment and checking for counterfeit currency. You can get the 18350 tube if you want your flashlight to be smaller.
Convoy S2+ Nichia 365nm UV $25.67
Convoy S2 LG 365nm UV 7135*3 with filter $19.41
Convoy S2 LG 365nm UV 7135*5 with filter $21.21
Convoy S2+ Black 18350 Tube
https://www.aliexpress.com/item/32629099377.html
EDIT:
Also read the post for more info about UV flashlights: