The Bike List

Klarus RS11 Flashlight £110

Tested by John Milbank, tester for The Bike List

I've been using Klarus flashlights for the last year or so of cycling - having reviewed the XT2C, the XT10 and the XT11, I've had a good chance to make use of the great value and performance they offer compared to bike-specific lamps. Being a flashlight, they're designed to pop onto the bike with a simple clamp (available separately for £4.95), then be easily removed when parking up. They're great for other activities too of course, and not having a separate power pack can be a real advantage…

Powered by a supplied 18650 rechargeable cell, my runtime test produced two hours and twenty minutes of light at full power. If you're out for a long ride, carrying one or two of the lithium ion cells in your pocket certainly won't break the bank. Also, being lithium ion, they don't have any memory effect, so there's no problem in topping them up every so often.

It's possible to helmet mount the RS11, and while it's not ridiculously heavy, you are slightly more aware of it than its smaller XT2C cousin. Fitted to the bars though, the light output is superb - offering a very even beam, full power is more than enough to light up the darkest off-road tracks. Medium mode, which gives over seven hours of light, is fine for most road work (and often preferable as 620 ANSI lumens at full-power will easily dazzle drivers). Low mode gives around 12 days of light, but is too dim for riding.

The RS11 has a slightly more textured reflector than the XT11, and combined with the higher output, it gives a slightly better light on the track. It's negligible though, and both the RS11 and XT11 use a cleaner, whiter LED than the XT2C and XT10 which are a little more yellow.

Sealed throughout with good quality O-rings, the Klarus is dust proof and waterproof to two metres. You also don't need to worry about the charging port - it won't affect it to get wet. As with their other lamps, the XM-L LED is protected by a toughened glass lens.

As the rear of the torch incorporates the charging port, the switch on this model has moved to the side. This makes for an easier hand position in day-to-day use, and is ideally suited to an easy touch with a gloved hand. A new feature is a memory function, with the lamp coming on in whatever mode was last used… great for cycling. Changing modes, and locking the light on, requires a one-second hold, which can be a little irritating on a trail, but you do soon get used to it. The other button on the unit instantly activates the strobe function - not much use when you're riding, but you never know when you might want to disorientate a would-be bike-thief!

As you can see from the runtime graph, the RS11 doesn't last quite as long as the other flashlights, though it is the brightest. Being a tactical torch at heart, it also continues the trend of reducing its output slightly after three minutes. In use, it's very hard to see the change, and it certainly doesn't affect your riding, while the digital control means it keep this brightness right until the battery dies.

It's when charging the RS11 that the flashlight really comes into its own. With a charging port on the back of the lamp, the supplied magnetic cable snaps quickly and simply into place (just like an Apple Mac laptop), allowing you to charge it from any USB port or charger. This means it's easy to top up whilst at work or in the evening - far more convenient than removing the battery and popping it into a charger.

Of course, convenience does come at a price, and while the RS11 offers incredible value for money when compared to bike-specific lighting systems, it's quite costly compared to its stablemates - the XT2C offers good performance for just £64 with a battery, and weighs a little less. There's also a remote switch available for the XT2C (and XT10/11), which some riders may prefer.

If you don't want to use a remote switch (I prefer not to), and convenience is really important to you, the RS11 offers incredible performance. While it's one of the dearer torch in the Klarus range, the built-in charger saves you money, and makes keeping the power topped-up really simple. When compared to some of the high-end bike-specific lamps, its a great deal.

At a glance


Klarus says:

Optional extras:

  • Swivel Bike Light Mount: £4.95
  • Helmet Mount: £4.95


  • LED Type: Ultra bright CREE XM-L (U2) LED with max output of 600 ANSI lumens and a life span of up to 50,000 hrs
  • Battery: 2x CR123A (3v) / 1x 18650 (3.7v) - any 18650 battery with PCB protection
  • Charging: USB charging via a patented magnetic charging point. Input - 5v. Output: 4.2v/ 500 mA max.
  • Charging Time: Depends on battery capacity. Formula is:
Charging Time = battery capacity / 500 mA + 0.5hrs
  • Function: There are 3 light modes and 1 flashing strobe mode.
  • Switch: Patented dual Switch operation; a protruding forward clicky switch for momentary-on, off and mode selection. A second (lower) switch provides instant dedicated strobe switch, which can be accessed from any mode when the torch is on or off.
  • Memory Function: The RS11 has a memory function that remembers the last mode you used. So, for example, if you need low level light, you can set the torch to activate in low mode - with both momentary-on and constant-on. A very intelligent feature!
  • Performance: The XM-L LED delivers a lot of bright light (620 ANSI lumens) and is an efficient performer due to the digitally regulated output, which maintains constant brightness.
  • Protection: Reverse polarity protection circuit protects against incorrect insertion of batteries. Springs at the head and tail of the flashlight protect the battery and maintain constant connection. Sealed with O-rings for excellent water resistance and improved service life. Waterproof to 2 metres and Dust Resistant to IPX-8.
  • Tactical: A stainless steel crenellated bezel at the front is removable and coloured filters can be screwed securely in its place. The dual-button system provides complete, one-handed control over light modes and instant access to strobe. The removable clip allows the torch to be clipped onto webbing, a tactical vest or Police stab vest.
  • Dimension: 143mm (Length), 36mm (Head), 24.3mm (Body)
  • Weight: 151g (without battery).
  • Finish: Tough, sealed body with HA Type III anodising.
  • Colour: Gun Metal Grey
  • Reflector: Orange peel to provide a smooth, flawless beam and good throw.
  • Lens: Toughened, ultra clear glass


  • Turn Power On/ Off
Press the higher switch for less than 0.6 of a second for momentary-on. Press for more than 0.6 of a second for constant-on. Press the switch to turn the light off.
  • Switch Modes
When light is on, press and hold the higher switch to change mode. Strobe is instantly accessible by holding down the lower switch. Strobe can also be accessed when the light is off, by pressing the lower switch.
  • Memory: When the light is on for more than 3 seconds, the mode will be memorised. Turn the light off, then the next time you switch the light on it will activate with the memorised mode.

Supplier: TacLight, 01274 561856,