You are buying C8F with LH351D 90 high CRI version, the rated max output is 3500LM, but actually according to the lower color temperature of LH351D (5000K or 4000K), the max output can be around 3000LM
Please know that 4000K is a bit yellow compared with 5000K.
It shares the same shell, same driver of standard version but has different leds.
※ 3* LH351D LED with a lifespan of 50,000 hours
※ Tints: 5000K cool white light; 4000K neutral white light; 3000K warm white light
※ Working Voltage: 2.8V-4.2V
※ Battery Options: One 21700 Li-ion battery(recommended) or One 18650 Li-ion battery
※ Dimension: 149mm (length)*44.6mm (head diameter)
※ Weight: 200±2 gram (without battery)
※ Flashlight body: Aerospace grade 6061 grade aluminum alloy, CNC manufactured to hard-anodized anti-abrasive finish to get solid built body, anti-crash geometry and better heat exchange.
※ Toughened mineral glass lens with AR coating.
※ IPX8 Waterproof (submersion up to a maximum depth of 1.5 m underwater for up to 30 minutes).
※ Protection from improper battery installation.
※ Advanced Temperature Regulation (ATR) technology: ATR will adjust the brightness level automatically when the driver temperature reaches 50℃ (122 °F) to prevent overheating.
※ Power Indicator:
The LED indicator on side switch blinks in green for 5 seconds when turns on.
LED indicator is Steady Green if the voltage is between 3.4 volt to 4.2 volt.
LED indicator is flashing Red if the voltage is between 3 volt to 3.4 volt.
LED indicator is rapid flashing Red if the voltage is between 2.8 volt to 3 volt.
The flashlight turns off automatically if the voltage is lower than 2.8 volt. Please insert new battery.
※ 4 Light groups:
Group 1: Moonlight- Medium; Turbo; Strobe
Group 2: Moonlight- Low- Medium- High; Turbo; Strobe
Group 3: Moonlight- Eco- Low- Medium- High; Turbo; Strobe
Group 4: Ramping (from Moonlight to Turbo)