The wand I received was defective, and Amazon issued a refund without even requiring a return or offering a replacement. Given the condition of the packaging, this was hardly surprising. The wand came in a flimsy cardboard tube, covered in wrinkled, yellowed sticky tape, and loosely wrapped in a plastic bag without protection. I fully expected it to be broken on arrival, and unfortunately, I was right.--Poor Design and Unclear Specifications--The product label reads "3W/5W," but it's unclear what that means, Does the wand use 3W or 5W? Does it alternate somehow? Are these max and min values? There are no buttons, switches, or indicator lights. To turn it on, you have to plug it in manually, which is awkward, especially given that it requires an external USB battery or outlet. This design flaw means you need to plug and unplug it while pointing it away from yourself, and it doesn't exactly come with a grip or stand. In use, your other hand is left holding the USB battery or struggling with a dangling cord, making it impractical for quick or safe operation.--No Indicators, Instructions, or Safety Warnings--With no indicator lights or visible glow, it’s impossible to know if this wand is on, especially given that the UV rays aren't necessarily visible. I tried several USB power sources (a battery pack, laptop, and outlet) and saw no sign it was working. Since I was fairly certain it wasn't giving off anything, I even looked directly into the lamp—something you should never do with UV devices—yet saw nothing.It's not like it says anywhere if it should glow. The product pictures suggest it does. Perhaps if I had full lab equipment, I could test with a microscope if this kills anything off when I can't see it do anything, but I don't have that.The lack of a user manual compounds this issue. It offers no guidance on how far away to hold the lamp, how long exposure should last, or any safety precautions. The product page seems to be the only "manual", and I can't imagine someone wants to navigate back to it whenever they want to check. Especially considering the page could disappear.Even more troubling, the product has no warning labels regarding UV light hazards. UVA and UVC light can damage skin and eyes within seconds of exposure.You may believe I'm overreacting over the dangers, but consider that another 3.8W UV lamp on Amazon includes a delayed-start feature to allow users to leave the room before it activates. Some wands even come with an automatic shut-off function when you hold them in an unsafe way. A product marketed at (up to?) "5W" should not be taken lightly according to every info I can find, and it’s shocking that this one arrives with no warning about potential dangers.Worst of all, the product pictures imply that you can "disinfect" your dog or other pets with it. For all that is holy, spare your poor pet the eye and skin damage and just give it a bath if it's so smelly.--Summary--In fairness, my wand didn’t work, so I can’t speak to its effectiveness. It could be a 1-in-100.000 broken product for all I know. The packaging makes me believe it broke in transport and that it's going to happen again, but hey, I don't know that. I wasn’t offered a replacement and wouldn’t have wanted one.Even if it did work, the design itself is flawed. You’re forced to provide your own USB power source, it lacks an on/off switch, has no indicator light, and the absence of a manual is irresponsible.If it functioned perfectly, I’d generously rate it 2.5/5. It's the absolute lack of safety features or warnings, as well as the awkward design that makes it difficult to use safely, as well as the picture that suggests shining it at your pet's face, which cements this as a rock solid 1/5.I'm by no means for excessive warning labels. Who would you hand out Darwin awards to if you made things too easy? But this is the opposite extreme.I don't normally write Amazon reviews and I'm not here to simply vent over a bad experience. But when I see a potential health hazard that I don't even trust my own hands with, let alone borrow to someone, let alone want anywhere near kids, let alone trust a random person with who might not know anything about UV rays, it's worth the effort. If you buy it, please know what you're doing.You can trust Amazon's refund policy, but you can't trust that they closely curate products from other vendors. They most definitely don't.