Never buy or use these. I admin a network with 20 of these phones in a manufacturing facility, the cases are a nightmare.
they're so awful that i cut them and redesigned because it caused all sorts of echo from the speaker bleeding back into the microphone, and clips were poorly built broke almost instantly.
very upset to see we bought so many of these and the phones, chargers, batteries, etc now there isn't a solution for carrying them.
the phones however work fine... still sucks to have in any work environment.