You asked for it, here it is. This is a spare battery for our flashlight. This 18650 is a 3500 mAh battery and has the built in fuse protection. This slightly more powerful battery does not make the light shine any brighter, but will give you about 3% more run time on all light settings over our 3400 mAh battery. Included with this battery is a silicone case which aids in protecting your spare, as well as preventing the spare from shorting out.