BlackBerry® 6700 Series specs at a glance:

6710: Large 160x160 pixel monochrome screen, 900/1900 MHz GSM/GPRS
6720: Large 160x160 pixel monochrome screen, 900/1800 MHz GSM/GPRS
6750: Large 160x160 pixel monochrome screen, 800/1900 MHz CDMA2000 1xRTT