The LIU collects seismic data in real time passed along a line of WRUs and forwards onto an Ethernet-based backhaul telemetry subsystem for transmission to Central recording system. Provide clock discipline to each line segment of WRUs allowing WRU to switch off GPS subsystem after WRU position is acquired. Dimensions: 24 W x 14 H x 36 L cm (5.42 Wx 9.44 H x 14.21 in.) Weight: 5.9 kg (13 lbs.)