There is only one
How is the build quality?
This flash was great as a secondary unit that I use with radio triggers. You have to shoot in manual mode since there is no E-TTL available as far as I can tell. There is only one pin on the hot shoe plate so I'm pretty sure if it's attached to your camera it doesn't do TTL. I think there is something about TTL off camera in the manual that is written in Chinese first then English so it wasn't quite as clear as it could have been. It really isn't a bother to me since I do shoot in manual mode when I set up the portable studio and the home studio as well but that's a whole other story. If you're in need of a bright flash of light for your photography then this can do it for a little cheaper than a Canon or Nikon flash. It has a solid build and feel to it and seems like it will last a while even with some banging around. The only thing I didn't like was the fact that it is much longer than my Canon 430EXII and took up some real estate in the camera bag. I think it is comparable to the Canon 580EXII.  I can get over that since it worked so good. 