Check the listing for details. EO-E1R (3.7V, 90 Lumens) Extreme Output Lamp for Surefire E1e, E1. Condition: New. Listed at 20.00 USD. This lamp is for 1 x 3.7V rechargeable battery setup for your E1e, E1. You can also use this on the E2, E2e, E2D, E2O if you are using a 1 x 17670 battery setup. With this lamp you can use 3.7V rechargeable batteries for you light to reduce battery costs. This lamp is also brighter then the stock Surefire lamp. This lamp is designed for 1 x 3.7V rechargeable battery setups ONLY, if you are using 1 x CR123A primary cell setups. Please purchase the HO-E1A. EO-E1R Extreme High Output 3.7V, 90 Lumens Extreme High Output Lamp Assembly (For 1 x RCR123A (16340) Rechargeable Battery, E Series Flashlights) -Extreme High Output Ultra High Pressure Xenon Lamp (90 Lumens) -Highest Achievable Colour Temperature (3300K) -Unique Filament Design -Precision Machined Aluminum Lamp Assembly -Every Lamp Assembly is Pre-Focused for the Ultimate Spot Compatible with: Surefire E1, E1E using 1 x RCR123A (16340) Rechargeable Battery E2, E2E, E2D, E2O using 1 x 3.7V Rechargeable BatteryE2D Incandescent Version using 1 x 3.7V Rechargeable BatteryM600B Scout Light using 1 x 3.7V Rechargeable Battery ***This lamp is designed for 1 x 3.7V rechargeable battery setups ONLY******NO REFUND or EXCHANGE if you are using any other battery setups and the lamp does not work*** Runtime (RCR123A (16340)): ~30 min Runtime (16670): ~70 min