... reversal polarity sign5.Have a LCD display call out number,call in number,time,billingmetering and etc.6.Caller id. With DTMF ... solve any problems.If you buy multiple items from us, we may support combined shipping and provide shipping charge discount.Payment ... working days.Via EMS: 5-7 working daysTracking Information - We provide tracking numbers whenever possible by email*SHIPPING WAY- EMS,UPS,FEDEX ...