By the looks of it, the device fits onto the case with its dial facing the user, latched onto the case using the side-panel screw. It connects to the system probably over the EVBot interface. Another possibility is that the device connects to the motherboard over USB (front-panel) headers. The meter's dial uses a GHz scale with starting unit at 1 GHz, going up to 6 GHz, with no distinct divisions between.
Source: TPU