... NO.Nation7128WH-BInput channels20/40 ChannelsPower supply4x 6V AA batteries, rechargeable batteries or external rechargeable lithium batteries ... , 0.03s, 0.1s, 0.2s, 0.3s, 1s, 2s, 3s (16Hz, 8Hz, 5.3Hz, 1.6Hz, 0 ... u Supports up to 40 EEG channels with expandable 4~8 channels for central leads, EOG, sphenoid electrode ... to 21 hours of continuous EEG monitoring with 4 AA batteries or up to 63 hours of ...