Foursevens just launched few several new light with burst mode.These flashlights are now capable of producing incredibly high lumens without affecting their run times! When switched to Max setting, flashlights with this feature will give you a massive increase in brightness for the first 60 seconds and then will ramp down over 30 seconds to 50% of that output. For somebody who already has Quark Turbo XML and wondering how this new Quark Turbo perform vs the classic one, scroll down for more information.
Spesification
Foursevens just launched few several new light with burst mode.These flashlights are now capable of producing incredibly high lumens without affecting their run times! When switched to Max setting, flashlights with this feature will give you a massive increase in brightness for the first 60 seconds and then will ramp down over 30 seconds to 50% of that output. For somebody who already has Quark Turbo XML and wondering how this new Quark Turbo XML-2 burstperform vs the classic one, scroll down for more information.
There is also Quark Turbo XML-2 without burst mode, to avoid confusion I'm just gonna call the new Quark Turbo XML-2 Burst with new QB2L-X burst and the classic Quark Turbo XML with classic QB2L-X.
MSRP: $89
available at foursevens
Quark Turbo XML-2 with burst is provided by Foursevens
Packaging And Content
Comes in clear blister pack, packaging look's clean and simple i really like the new foursevens packaging design compared with classic one. I really like the included battery, in case you are not flashaholic your light is always good to go out of package !! Also they included rubber hand grip which they don't included on classic QB2L-X. Inside the packaging you got:
- 1 x Quark Turbo XML2 Burst
- 1 x Lanyard
- 1 x Holster
- 1 x Manual
- 1 x Rubber Hand Grip
- 2 x Primary CR123
- 2x Spare O-Ring
Nothing much changed on new QB2L-X burst, only aesthetic design changed ( you can see the details below ). I also found the clip is more stiff on the newQB2L-X burst, i found little bit difficult to clip it on my pocket. Knurling i would say medium traction, traction is about the same with the classic model. Pocket clip is removable.
New QB2L-X burst has 3 piece body design from head - battery tube - tail cap. The is a hole on tail cap to attached lanyard if you need to. Head and tail cap is reverse-able, you can switch it to get more carry option bezel up or bezel down.
The thread is squared cut for smooth twist and more wear resistance compared with non squared cut thread
Size is compact enough it's fit my palm very well. Also you still can do pocket carry fairly comfortable with it's size.
Comparison with Classic Model
Overall design is quite similar between new QB2L-X burst with burst and classic QB2L-X. The difference is on new QB2L-X burst the don't have Foursevens brand on battery tube.
The other difference which i think important, on new QB2L-X burst the tail switch is not anodized while they put anodized on classic QB2L-X. So you can't lock out your flashlight to prevent accidentally turned on. I don't know why Foursevens does not put anodized on the new QB2L-X burst tail cap.
You can see also the anodizing is more matte in new QB2L-X burst compared with classic QB2L-X which more glossy. I like it this way. Maybe in the future if Foursevens could do matte black anodize finish like Armytek Predator anodized, it would be awesome !!!
User Interface, Output and Beam Shot
Switch is Forward Switch which is you can do half press to do momentary and full press to get constant on.
New QB2L-X burst basically has 2 mode, with head fully tightened is mode 1 and head loosened mode 2.
To reprogram the each mode ( let's say with head fully tightened), you need to loosen-tighten the head 4 times quickly ( you can also do loosen-tighten more than 4 times it does have to 4 times). After 3 secs, the light will flash 3 times, and you can now choose through all the possible modes by soft-pressing or clicking off-on at the tail switch. To select the mode you want memorized, wait 10 secs with the light on in that mode. The light will flash rapidly to give you indication that the current mode has been memorized. It won't change unless you go through the programming mode again.
At the max mode, burst is only for 1 min, during 1 min output is gradually dropped without noticeable difference. But in case you need the burst mode again, you can turn off the flashlight then turn on again to get burst mode.
Equipped with the latest Cree XML-2 and on my sample emitter is perfectly centered. New QB2L-X burst is using smooth reflector.
As you can see at max mode the New QB2L-X burst is noticeably much more brighter than classic Quark QB2L-X. On 175 meter distance it still light up the object very well, it's incredible for such a compact light 
I don't do moonlight mode distance shot because it's just about the same as control shot and the light is way too dim. As you can see, there is not much different in every mode except at max mode. The output is fairly compare-able in every mode.
On Max mode, New QB2L-X Burst is driven harder than classic QB2L-X.
On Primary CR123 after burst mode New QB2L-X burst output is gradually stepping down without noticeable drop, stabilized around 500-ish lumens while on classic QB2L-X output is stabilized 270 - 350-ish lumens.
On RCR123 after burst mode output on new QB2L-X burst is gradually stepping down without noticeable drop, stabilized around 500-ish lumens while on classic QB2L-X output is stabilized 250 - 350-ish lumens. Please note, when you are using RCR 123 the light will suddenly go off when the battery is completely depleted, while on Primary CR123 it's still give you dim light.
Update on 20 August 2013: I just measured tail cap reading using Sanwa DMM ( Digital Multi Meter).
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Using fresh AW RCR123: On new QB2L-X burst reading @ 1st second is 1700 mAh and gradually stepping down ( did not continue measure ) while on classic QB2L-X reading @ 1st second is 750 mAh ( continued measure for ~10 secs, it's stabilize between 745-750 mAh ).
- Using fresh Primary Surefire123: On new QB2L-X burst @ 1st second is 2810 mAh and greadually stepping down ( did not continue measure ) while on classic QB2L-X reading @ 1st second is 1,120 Amp ( continued measure for ~10 secs, it's stabilize between 1,120 - 1,110 mAh ).
At max mode on New QB2L-X burst both on RCR123 and CR123 current is quite high and it's not safe for the battery if it driven continously but for 1 min i think it still safe. Foursevens did a good job on driver design by stepping down the current gradually.
On QB2L-X burst because it's driven harder at max mode you will get less run time than the classic QB2L-X. Output on New QB2L-X burst is more flat than ClassicQB2L-X.
Summary
These two quark turbo shared identical design and feel while you hold on your hand. It's good that Fourseven included the rubber grip on New QB2L-X burst, in case you need yo don't have to buy it separately the new QB2L-X burst does not comes with anodized tail cap so you can't lock-out the light also the clip is much more stiff than classic QB2L-X, i feel little bit difficult to clip it on my pocket.
The is not much different in every mode except at max mode. At max mode, the new QB2L-X burst is driven harder than classic QB2L-X which always been trade off with more lumens you will get less output. The output on new QB2L-X burst is more flat than output on classic QB2L-X.
Suggestion for Foursevens: Please make the tail cap anodized and improve the anodize like ArmyTek did on their Armytek Predator light 
Hope you guys enjoyed my review!
