Fenix TK21R Reference Manual and SpecificationsUpdated 2 hours ago

The Fenix TK21R is a duty flashlight. This summary is drawn from the manufacturer's official user manual — see the downloadable PDF reference manual on the product page for complete details.

Warning

Do not place this light within reach of children.
Do not shine the light directly into the eyes of anyone.
Do not place the light head near flammable objects; high temperatures can cause objects to overheat and become flammable/ignite.
Do not use the light in inappropriate ways such as holding the unit in your mouth — doing so could cause serious personal injury or death if the light or internal battery fails.
This light will accumulate a significant amount of heat while operating, resulting in a high temperature of the light shell. Pay close attention to avoid burns.
Remove the battery to prevent accidental activation when the light is placed in a closed and flammable environment such as pockets and backpacks.
The LED of this light is not replaceable; the whole light should be replaced when the LED reaches the end of its lifespan.

Product Features

3600 lumens maximum output, 480 meters maximum beam distance
One Luminus SFT90 LED with a lifespan of 50,000 hours
Powered by one Fenix ARB-L21-6000 rechargeable battery
Advanced Pulse-Frequency Transmission System (APF)
Dual tactical tail switch for instant activation and instant strobe
Hidden USB Type-C charging port supports fast charging
Internal dual-spring structure ensures stable lighting even under severe impact
Made of durable A6061-T6 aluminum
Size: 6.04'' x 1.42'' x 1.00'' / 153.5 x 36 x 25.4 mm. Weight: 7.81 oz / 221.4 g (including battery)

Operating Instructions

Switches: the round tail switch is the tactical switch for instant burst; the oval tail switch is the functional switch for output selection and instant strobe.

On/Off: tap the tactical switch to turn on the light silently, release it and the light will go out. Fully press the tactical switch to constantly turn on/off the light.

Output Selection: with the light turned on, single click the functional switch to cycle through Low, Med, High, and Burst.

Instant Burst: fully press the tactical switch for 0.5 seconds to enter Burst and maintain this output.

Strobe Mode: with the light turned off, tap the functional switch to enter Strobe, release it and the light will go out. With the light turned on, press and hold the functional switch for 0.5 seconds to enter Strobe, tap either switch again to exit Strobe and recall the previously used output, or fully press the tactical switch to turn the light off.

Intelligent Memory Circuit: the light automatically memorizes the last selected output, excluding Strobe. When turned on again, the previously used output will be recalled.

Technical Parameters (ANSI/PLATO FL1)

Burst: Output 3600 lumens, Runtime 2 h 30 min*, Distance 480 meters, Intensity 58,000 cd.
High: Output 1000 lumens, Runtime 3 h 30 min, Distance 260 meters, Intensity 17,000 cd.
Med: Output 350 lumens, Runtime 7 h 30 min, Distance 150 meters, Intensity 5,860 cd.
Low: Output 30 lumens, Runtime 72 h 30 min, Distance 45 meters, Intensity 500 cd.
Strobe: Output 3000 lumens.

Impact Resistance: 1 meter | Water Resistant: IP68 (Submersible)

Note: according to the ANSI/PLATO FL1 standard, the above specifications are from the results produced by Fenix through its laboratory testing using one Fenix ARB-L21-6000 battery under the temperature of 21±3°C and humidity of 50%-80%; the true performance of this product may vary according to different working environments and the actual battery used. *The Burst output is measured in total of runtime including output at reduced levels due to temperature or the protection mechanism in the design.

Battery Specifications

Fenix ARB-L21-6000 (21700, 3.6V): Recommended.
Fenix ARB-L21-6000B (21700, 3.6V): Recommended.
Fenix ARB-L21-5000 V2.0 (21700, 3.6V): Recommended.
Fenix ARB-L21-5000U (21700, 3.6V): Recommended.
Fenix ARB-L21-4000P (21700, 3.6V): Recommended.

Do not use an 18650, CR123A, or 16340 battery. 21700 Li-ion batteries are powerful cells designed for commercial applications and must be treated with caution and handled with care. Using low-quality batteries or mishandling batteries (such as short-circuiting or overheating) could lead to combustion and jeopardize the safety of users and property. Any adverse effects resulting from the use of low-quality batteries are not covered by any Fenix warranty or liability. Using quality batteries with circuit protection will reduce the potential for combustion or explosion.

Battery Replacement: unscrew the light tail and insert the battery with the anode side (+) towards the light head, then screw the light tail back on.

Charging

Unscrew the light neck counterclockwise to reveal the charging port, then connect the USB Type-C end of the charging cable to the light.
The indicator will display red while charging and will turn green when fully charged.
Once charging is completed, be sure to unplug the charging cable and screw the light neck back on to maintain the dustproof and waterproof ability.

Note: when charging fails or the battery is reversely connected, the battery level indicator will flash red or remain off to remind users to check the battery. The normal charging time of the included Fenix ARB-L21-6000 battery is approximately 1.5 hours from depleted to fully charged. Recharge a stored light every four months to maintain optimum battery performance. The light cannot be operated while charging. It is strictly prohibited to charge the light while using an 18650, CR123A, or 16340 battery.

Battery Level Indication

Each time the light is turned on, except for Strobe, the indicator (unscrew the light neck to see) will indicate the battery level and will last for 3 seconds.
Green light on: saturated, 100% - 85%.
Green light flashes: sufficient, 85% - 50%.
Red light on: poor, 50% - 25%.
Red light flashes: critical, 25% - 1%.

*This only works with a Fenix ARB-L21 series rechargeable battery.

Intelligent Overheat Protection

The light will accumulate a lot of heat when used at high output levels for extended periods. When the light reaches a temperature of 55°C/131°F or above, it will automatically step down a few lumens to reduce the temperature. When the temperature drops below 55°C/131°F, the light will gradually recall the preset output level.

Low-Voltage Warning

When the voltage level drops below the preset level, the flashlight is programmed to downshift to a lower brightness level until Low output is reached. When this happens in Low output, the flashlight blinks 3 times every 5 minutes to remind users to recharge or replace the battery in a timely manner. This only works with a Fenix ARB-L21 series rechargeable battery.

Usage and Maintenance

Disassembling the sealed head can cause damage to the light and will void the warranty.
Fenix recommends using an excellent-quality battery.
If the light will not be used for an extended period, remove the battery, or the light could be damaged by electrolyte leakage.
Unscrew the light tail half a turn or take out the battery to prevent accidental activation during storage or transportation.
Long-term use can result in O-ring wear; to maintain a proper water seal, replace the ring with an approved spare.
Periodic cleaning of the light and battery contacts improves the light's performance, since dirty contacts may cause flickering, intermittent operation, or failure to illuminate — check for a poor battery level or dirty contacts, and contact the distributor if cleaning doesn't resolve it.

What's Included

Fenix TK21R flashlight, ARB-L21-6000 battery, USB Type-C charging cable, Holster, Lanyard, 2 x Spare O-rings, User manual, Warranty card.

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