This is a Streamlight Original, not an aftermarket battery, so you know it will work perfect with your Streamlight Flashlight. This battery fits the Streamlight UltraStinger Flashlight and the Streamlight SL-20XP LED Flashlight.
Battery Stick (SL-20XP-LED, UltraStinger) (NiCad Batteries).
Streamlight UltraStinger & SL-20XP LED Replacement Battery
WARNING: This product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov