Last Updated on November 12, 2026
Fenix makes lights ranging from small AA pocket models to full-size tactical flashlights. The TK20R sits toward the duty end of that range. It gives you a tail switch for a quick look and a beam with enough reach to check a trail or driveway.
This Fenix TK20R review covers the original 1,000-lumen model and the 3,000-lumen V2.0. On the original, look for a side button and a micro-USB port under a rubber cover. The V2.0 puts both controls at the tail and hides its USB-C port under a threaded collar. Those differences tell you which cable, spare battery and switch instructions you need.
Fenix TK20R V2.0 vs TK16 V2.0 vs PD35 V2.0
The Fenix TK20R V2.0 and the Fenix TK16 V2.0 have similar peak output. The TK20R throws its beam farther and charges through the body. The TK16 has a shorter body and charges through the port on the supplied battery. The PD35 V2.0 is the slim option for an 18650-based kit.
| Model | Peak output and beam | Battery and charging | Controls and size |
|---|---|---|---|
Fenix TK20R V2.0 Check Price | 3,000 lumens · 475 m · 56,600 cd Luminus SFT70 | One approved 21700. USB-C port under the body collar. | Two tail switches. Five brightness levels and strobe. 6.02 in. |
Fenix TK16 V2.0 Check Price | 3,100 lumens · 380 m · 36,100 cd Luminus SST70 | One approved 21700. USB-C charging on the supplied battery. | Two tail switches. Five brightness levels and strobe. 5.63 in. |
Fenix PD35 V2.0 Check Price | 1,000 lumens · 250 m · 15,600 cd Cree XP-L HI V3 | One 18650 or two CR123As. Use an external charger for a rechargeable 18650. | Tail power switch and side mode button. Five brightness levels and strobe. About 5.4 in. |
If your light is marked PD35 TAC, you have the Tactical Edition with a 200-meter rated beam. The PD35 V2.0 in the chart has a 250-meter rating. Our Fenix PD35 version comparison covers the V2.0 and V3.0 for readers who want a smaller light.
Quick Overview
The original Fenix TK20R takes one rechargeable 18650 or two CR123A primary batteries as a backup. It has four steady levels, a strobe, reverse-polarity protection and a low-voltage indicator. The V2.0 has a higher peak output and the convenience of a second switch at the tail. The original is the better fit if you already keep an 18650 kit and like a side button you can reach with your thumb.
For a smaller 18650 light with built-in micro-USB charging, see the review of the Fenix UC35 LED tactical flashlights. It gives you another way to compare size and beam distance if you already use this battery type.
Technical Specifications of the Fenix TK20R LED Flashlight
| Feature | Original TK20R |
|---|---|
| Maximum output | 1,000 lumens with a Cree XP-L HI V3 LED. |
| Maximum beam | 310 m (about 339 yd) and 24,000 candela. |
| Brightness levels | 10, 150, 350 and 1,000 lumens, plus a 1,000-lumen strobe. |
| Battery | One 2,900 mAh 18650 included. An approved 3,500 mAh 18650 or two CR123A primaries can also power it. |
| Charging | Micro-USB on the body for an approved rechargeable 18650. About 3.5 hours under the manual’s stated charging conditions. |
| Size and construction | 6.0 in long, 1.3 in across the head and 5.0 oz without the battery. Anodized aluminum body and coated glass lens. |
| Water and impact | Original manual lists IPX8 for 2 m immersion and a 1 m drop-test rating. |
| Included with the light | Charging cable, holster, lanyard and a spare O-ring. |
Our Fenix TK20R Review
The original version is still straightforward to use if you already own it. Your thumb can reach the side button in a regular grip, and the tail switch can give you a quick burst without a full click. The battery is removable, so you can swap in an approved spare while the first cell is depleted.
How bright is the Fenix TK20R flashlight?
Turbo on the original is rated at 1,000 lumens and 310 meters. The 350-lumen High setting is often the more practical choice for longer checks around a yard. The 150-lumen Medium setting gives you a softer beam on light walls, and the 10-lumen Low is useful for reading a map or checking something near your feet. For longer distances, pay attention to the bright center of the beam and how much of the area around it stays visible.
The 310-meter figure describes the manufacturer’s beam-distance test. Details like a dark marker or a small object on the ground are easier to identify much closer. Keep the higher settings for the stretches where you actually need the reach.
Is the flashlight durable enough?
The aluminum body has a hard-anodized finish and the LED sits behind coated glass. The clip and included holster give you two ways to carry a light this size. At about six inches long before you count the lanyard, it is easier to keep on a belt or in a jacket pocket than clipped inside a shallow pants pocket.
What type of battery is required?
Use one approved 18650 in the original TK20R for routine charging. Switch the light off, lift the dust cover and connect a micro-USB cable. A red indicator shows charging. Green shows a full charge. Press the cover back into place before taking the flashlight out in wet conditions.
Two matching CR123A primaries can power the original when a rechargeable cell is unavailable. Remove them before connecting USB power. If you use the Fenix UC30 USB flashlight or other Fenix lights with a similar port, check the battery and charger instructions for each one before sharing spares.
Does the Fenix TK20R flashlight have a strobe mode?
Yes. Turn on the original with the tail switch, then hold the side button for about half a second to enter strobe. A brief press of that button returns to the previous brightness. You can also tap the tail switch partway for momentary light or press it fully to keep the light on. The light remembers the last steady setting.
Is the Fenix TK20R water- and impact-resistant?
Fenix lists the original TK20R at IPX8 for immersion to two meters under its test conditions and rates it for a one-meter drop. Check the port cover and tail-cap O-ring before wet use. A cover that has lifted or a seal that has picked up grit deserves attention before the light goes back in the rain.
What is the maximum runtime?
The original has two 18650 runtime columns in its manual. On Low, the supplied 2,900 mAh battery is rated for 135 hours, and the approved 3,500 mAh test cell is rated for 160 hours. The turbo times are estimates that include heat protection. Use the High or Medium figures when you plan to keep the light on for an extended job.
| Mode | Output and beam | 2,900 mAh | 3,500 mAh |
|---|---|---|---|
| Turbo | 1,000 lm · 310 m | 1 h 30 min | 1 h 50 min |
| High | 350 lm · 193 m | 4 h | 4 h 20 min |
| Medium | 150 lm · 126 m | 10 h 30 min | 11 h |
| Low | 10 lm · 31 m | 135 h | 160 h |
What are the additional features?
The light has reverse-polarity protection and a startup battery indicator with an approved rechargeable cell. If the beam drops from Turbo after a few minutes, let the light cool and check whether a lower steady setting works normally. A flashing red battery indicator and a drop to Low call for charging or replacing the cell.
Does the flashlight offer a warranty?
Fenix’s published service policy gives removable-battery flashlights five years of repair coverage for faults that arise under normal use. The battery has separate terms. Fenix Lighting USA lists its own limited lifetime guarantee. Keep the receipt so the seller can apply the terms for your market and purchase.
What Changes on the Fenix TK20R V2.0?
The V2.0 is the useful upgrade for a longer beam and both controls under your thumb. Its round tail button handles momentary and continuous light. Use the oval button to cycle through Eco, Low, Medium, High and Turbo while the light is on. Press the oval button while the light is off for momentary strobe. The round button recalls the last steady level.
The V2.0 uses an approved 21700 such as the included 5,000 mAh cell. Loosen the threaded cover to expose the USB-C port, connect the cable and wait for the indicator to turn green. A full charge takes approximately 3.5 hours with the included battery. Tighten the cover after charging. Keep your original TK20R’s 18650 or CR123A spares for the original light.
| Mode | Manufacturer rating |
|---|---|
| Turbo | 3,000 lumens · 475 m · 2 h 50 min, including reduced output after step-down. |
| High | 1,000 lumens · 265 m · 3 h 10 min. |
| Medium | 350 lumens · 150 m · 7 h. |
| Low | 150 lumens · 100 m · 21 h 20 min. |
| Eco | 30 lumens · 45 m · 48 h. |
Fenix rates the V2.0 IP68 with the charging cover closed. It uses a Luminus SFT70 LED and weighs about 7.2 oz with the battery. If you need a dedicated lock position and a separate choice of Tactical and Duty modes, the TK20R UE uses a FlexiSensa selector and is rated at 2,800 lumens and 465 meters. The original, V2.0 and UE each have their own controls.
Fenix TK20R V2.0 flashlight and charging kit Check Price
Troubleshooting for the Fenix TK20R Rechargeable Flashlight
| Issue | What to check | What to do |
|---|---|---|
| Light will not turn on | Battery charge, orientation and tail-cap contact. | Fit the approved battery with its positive end toward the head and seat the tail cap. |
| Beam flickers or looks dim | Weak battery or loose or dirty contacts. | Turn off the light. Check that the cap is snug and try a fully charged approved cell. |
| USB charging fails | Connector type, cable, power supply and battery. | Use micro-USB on the original or USB-C on the V2.0. Test with an approved rechargeable cell and a known working cable. |
| Turbo drops or the head gets warm | Heat protection during high output. | Switch to a lower mode and let the light cool before trying Turbo again. |
| Modes will not change | Which generation you have and which switch you are pressing. | Turn the light on. Use the side button on the original or the oval tail button on the V2.0 to change steady levels. |
| Water appears inside | Port cover and tail-cap seal. | Switch off the light and keep it off the charger. Contact the seller for service if moisture has entered the body. |
| Runtime is short after charging | Battery age, usual mode and indicator status. | Compare a fully charged approved cell on the same steady mode. Replace a worn pack with a supported model. |
Why buy a Fenix TK20R USB rechargeable flashlight?
- The original combines 18650 power with a useful 10-lumen Low setting and micro-USB charging.
- Both versions have a momentary tail switch, several steady modes and a removable rechargeable battery.
- The V2.0 puts the mode switch beside the power switch and gives you more reach for larger outdoor areas.
Cons
- A slim pocket light is easier to carry for short indoor tasks.
- The original’s raised tail switch makes it difficult to stand upright.
- The V2.0 requires its approved 21700 battery family, so an 18650 spare kit needs a separate light.
Conclusion
The original Fenix TK20R still makes sense for an owner who prefers a side mode button and already carries 18650s. The V2.0 is easier to recommend if you want USB-C, two tail switches and a longer beam. If most of your tasks are at arm’s length, a smaller Fenix E12 may be easier to keep with you.
Fenix TK20R V2.0 Check Price
FAQ
Can I use the side switch to turn the flashlight on and off?On the original, the tail switch controls power. Use the side button to change brightness or enter strobe once the light is on. Both controls on the V2.0 are at the tail.
Is it possible to turn on the strobe mode using the back button?On the original, turn the flashlight on and hold the side button for about half a second. The V2.0 gives you momentary strobe from its oval tail button while the light is off.
Can the flashlight tail stand?The original TK20R’s raised tail button makes upright use unstable. Put it on a stable surface on its side or use the holster when you need to set it down.
Can the two generations share a battery?The original uses an approved 18650 for rechargeable use. The V2.0 uses an approved 21700. Check the model marking before buying a spare, and follow the manual for the cell and charger.