... sim dual standby,supports GPRS,MMS 2.Back-up battery Apphone, Backup power for iphone 4 & 4s, dual sim card case ( ... iphone 4&4s, protection,fashion,multifunctionsupports two sim cards(WCDMA & GSM), GPRS, MMSLarge back up battery capacity, change iphone4 anytime anywhere ... exp ctn:38gGross weight of exp ctn:5238g dual sim battery case for iphone4 iphone4s with extra card supporting GPRS MMS SMS