... are following models which can be selected.ProductModelNoteCDMA MODEMH6811USB Interface, Wavecom module inside, 800 Single band, 800/1900Mhz Dual band optional ... . Either +5VDC or +7.5~26VDC. H6821-WRS-232 Interface, Wavecom module inside, 800 Single band. Either +5VDC or +7.5 ... ~26VDC. H6821-W2RS-232 Interface, Wavecom module inside, 800/1900 Dual band. Either +5VDC or +7 ...