ePathChina has a more preferential price than other manufactuers, service and products are not bad, however, shipping is sometimes slow by airmail. But they explained that postal mail is always like that because they are cheap. DHL is always fast though. Hope to deal with them again !
Beaufort
How does dual SIM work?
The answer to this question all depends on the phone.
Some types of unlocked phones have two CPUs (central processing units, the part of the phone that does the 'thinking') which allow them to make two calls at the same time. You can receive signals for both numbers.
Not all dual SIM card phones have two CPUs and this can have two results for consumers. If the phone has "call secretary" software, or your carrier has an "online call secretary" service, then when another call comes in, and you're busy, the incoming call will go to voicemail. If no such software or option exists on your GSM dual mobile then the other caller will just be told that your line is busy.