Hi,
besides at what companies to look at, you should consider the following criteria:
- arm length should be at least 25-30cm (10-12 inches)
- you should be able to remove / disconnect the batteries completly (important for air travel)
- if you are using just one strobe it should have a broad lighting angle (not sure wether this expression is correct, though). What I mean by that is, that it should cover a large area.
To become a little more specific here, it would be good, if you could provide some more info (e.g. What kind of pictures you intend to take (e.g. Macro) and maybe how much your budget for this is.)
Regards, Marc