The 4Sevens 1xAA Quark with 14500 lithium ion (rechargeable) battery in it = WOW! It will knock your socks off, both in brightness and price. I love mine. None of my keychain lights have lasted terribly long. And that includes an ARC 1xAAA, supposedly a very good light (no longer made). So I went to slightly bigger and more expensive lights. I'm much happier with now.