I bought this 17670 battery to replace two cr123 batteries in my older model streamlight protac HL headlamp. While the battery fits fine, the voltage is too low and the light does not work. This is no fault of the battery. This headlamp requires the voltage of two cr123 batteries in series, 6v, to operate.

Does not work in my (late 80s? early 90s?) 6P or early 90s 12Z SureFires. But I do have a (mid 90s?) 6Z that it powers, although not as bright as 2 CR123s (which is ).

Fits perfectly in my surefire lights. Works great

I use flashlights all day every day. I keep a Streamlight 2xCR123 on me and chose a model that couldn't take 18650s because they are significantly larger. This battery last longer than 2 CR123 rechargeables and has worked reliably every day for over a year.

I have other ultrafire 17670 batteries. These seem a bit slimmer where the protection circuit is installed. This allows these batteries to fit easily in a Surefire G2 and Surefire 6P whereas the the older ones I have are either tight fit or unable to fit. I have a couple of other lights that I have never been able to get a full size lithium ion battery to fit and these fit quite well.

Thanks