[Single] Have the Lumedyne X and love it performs much like a mimi cycler for speedlights. Very small and compact and plugs directly into the flash so no cords to get tangled in. Performs as advertised doubles the life of the onboard batteries and cuts the recycle time in half. Not as fast as the big belt cyclers on full flash dumps but with higher ISO and TTL use you may not notice any difference. The X also maintains the flash capacitors at full charge for more consistent results. Normally the capacitors loose some of their charge before topping off again from the onboard batteries. Performs very different and better than the cheep Chinese extra batteries that only extend battery time but do nothing to speed up the recycle time of the flash. Save your money and get the Lumedyne X it's a much more useful and a real photographers tool. Once you get used to using the X or a Cycler and your flash fires every time at the correct intensity it's hard to settle for the basic performance and missed shots that the onboard batteries alone provide. I find that the Lumedyne X now lives in my camera bag as a light weight alternative to a cycler battery pack. It's great to have cycler performance at hand without the weight penalty of dragging it around if you don't need it or use it. Great for traveling less stuff, less weight! I'm a professional wedding photographer and found the Lumedyne X to be a great and useful addition to my bag. Very handy when dealing with two bodies, no tangled cycler cords. Also love the USB charger that lets me recharge in the car between locations. Lumedyne, is also a great company that really stands behind it's products that are made in the USA.

[330.0 VDC] This is a very nice upgrade form the original battery pack. The charge time is slower than the lithium battery.

[1.3 to 4.0 Sec ] This works great and vertical video mode is awesome!

[Yes] I was looking for an external power pack for my Canon 580EX speedlight, something more environmentally friendly and the Lumedyne Supercycler match my needs. I bought the Medium battery to go along with the Supercycler. Sure, it costs more than the other external power packs but I can fire at least 800+ full power flashes. I don't recommend you do that, however, you'll be in the market for a new flash because it's easy to forget most Speedlight manufacturers tell you to shoot no more than 20 continuous full power flashes.

[1.05 lb] The X flash accelerator is very easy to use -just hold the on/off button for 3 seconds and go. The accelerator works as advertised. It not only recycles fast for a longer time but helps the flash batteries last longer. It is small, compact and better than the larger belt ones with their cables. You can discuss the its performance with their support person.

[1.3 to 4.0 Sec ] I purchased the SuperCycler with Large Battery to replace the Quantum Turbo battery pack for my Q-Flash. I use Q-Flash when photographing weddings. I can shoot all day long - including fill flash in direct sunlight - and still have battery power. The Large Battery lasts about the same as 3 Turbos. Extremely reliable. I purchased a small shoulder bag to hold the SuperCycler/Large Battery combination. DO NOT USE the Lumedyne strap adapter - it's totally useless.