I have mine on my keychain, I got the w1 emitter and it's very bright and white, it's even bright considering I have a AAA battery in it not a lithium battery, the reason I have the AAA is too fold, so such a small light dosnt get too hot, and also so I can leave it in extreme temperatures, I bought 5 of these and handed them out to family
Have the W1 and the UV, they're extremely bright!