I bought these on ebay for £24, including free postage, and they were delivered from Hong Kong to England within 7 days. Here are shots of the retail packaging:
The set I chose consisted of two receivers and one transmitter/trigger. The items are surprisingly small and are pictured below alongside a 50p coin and a 67mm lens cap for scale:
Here are the supplied instructions, on a folded sheet of A4 paper:
Here are shots of a Canon Speedlite 430EXII mounted on the receiver which screws directly on to the top of a light stand:
To set the Canon Speedlite, (a) press the Mode button for two seconds to set the flash to manual, (b) press the Select/Set button for one second, and then (c) press the + or - button to set the power from 1/1 down to 1/64:
Here's the Speedlite mounted on the receiver which can also slide on to a (cheap ebay) umbrella clamp:
Here's the transmitter on my Canon EOS-450D and, as you can see, it's small and unobtrusive:
For Canon users, here's the radio transmitter compared to the expensive Canon ST-E2 infra-red transmitter:
Each receiver takes two AAA batteries, which were not supplied but I did have four rechargable NiMH handy.
The transmitter is powered by a supplied 23A 12V mini-battery but I am concerned about the tiny screw that will eventually have to be opened. It's so small that I couldn't turn it with the screwdriver that I use for opening laptops and removing and installing hard drives. I think I'll have to find a screwdriver that's small enough for adjusting screws in spectacles!
The kit has a reputed range of 20 metres which is greater than the Canon ST-E2 Transmitter (8m outdoors and 12m indoors). I was able to test it indoors at about 10 metres with the flash in one room and me in another. I also placed the flash behind a sofa and it was successfully triggered.
In conclusion, this is a cheap way of wirelessly triggering one or more flashguns off-camera. The kit can be used with any brand of flashgun so, if I did change from Canon, I wouldn't have to sell my two Speedlites. The downsides are the build quality which appears satisfactory and only time will tell how long the components last; and the fact that users will have to learn manual flash settings.
Personally, I think I'm ready to make the jump from the easy-to-use-but-expensive Canon ST-E2 Transmitter (which will probably be put up for sale) and solely use these radio transmitters.
If you have any questions, please ask and I'll do my best to help.