Multi-Fuel: Uses (1) Streamlight SL-B9 protected Li-Ion USB-C rechargeable battery pack (included) or (1) CR123A lithium battery; SL-B9: 1000 lumens, 22000 candela, 297m beam, runs 30 minutes; CR123A: 500 lumens, 11000 candela, 210m beam, runs 1.5 hours; Safe-off feature prevents accidental activation; saves batteries; Engineered optic produces a concentrated beam with optimum peripheral illumination; Securely attaches to long guns with MIL Standard 1913 rails; IPX7 waterproof to 1m for 30 minutes; "Light Only" model - Includes key kit, (1) SL-B9 rechargeable battery pack, and USB-C cord; "System" model - Includes key kit, mounting hardware, momentary pressure switch, (1) SL-B9 battery pack, and USB-C cord