LIGHTFE UV Mini 01D Blacklight Flashlight 365nm Keychain lamp, Suitable for pet Urine Stains, Stains, Minerals, Fluorescent Agent Detection, and Currency Art Identification, etc

This thing is awesome. I keep it in my back pocket and the twist-on/off is stiff enough and has enough threads that it doesn't go on automatically or unscrew accidentally. They also give you a mess of extra batteries with it. It's got gaskets so it looks like it's waterproof. It's not terribly bright but if you expect a flashlight the size of the last digit on your pinkie to be bright, you're living in an alternate universe. Very happy with this. I guess the only thing I would (did) change is that the little clevis on the back was a little loose, so I pinched it in some so that it wouldn't come off the key ring.

HILARIOUSLY OVER_PACKAGED. The flashlight is less than an inch long and it came in a small box inside a HUGE box stuffed with paper. PEOPLE: A PADDED ENVELOPE WOULD DO JUST FINE. Wonderful little light—very bright and virtually weighless for car keys or purse.

Perfect little black light to take into concerts to charge the glow-in-the-dark little resin duckies to pass out.

The metal loop to hold it to your key ring is not strong or well made or thought out. Light is bright, but not good if you lose it. It's fallen off twice, and by chance it was while walking to my car so I saw it later. Eventually it will get lost, and it's not easy to substitute the loop to hold onto key chain as it is so small.

These will work well, the batteries are not the easiest to find, but not too hard either.

Why did you pick this product vs others?:The tiny size

Being 365nm instead of 395nm greatly improves the ability to detect faintly flouresent items. Very bright for it's size.

UPDATE: seller reached out to me without me contacting them and refunded my money. So based on all things I change my rating to 5 stars.Would not recommend for use on key ring. The flashlight turns on and off by twisting the 2 pieces of the flashlight.I bought it to put on my key ring. The 2 pieces of the flash light worked itself apart from putting my keys in and out of my pocket and the bottom piece of light was lost. It only took 3 days for this to happen.If you turn the bottom portion tight and snug the light remains on and lasts only about 3 mins before it goes dim. So the bottom of the light is only twisted about 2/3rds up. It id why I believe my light twisted off so quickly.Would have lasted longer if it had an on and off button. So I would not recommend at all.