The model TM-3A is intended for collecting the mercury present in gas as a gold amalgam and then continuously measuring it on an unmanned basis. The model has the ultrahigh sensitivity of 0.2 pg as the lower detection limit, thus enabling short-time measurements repeatedly. It is also capable of automatically making standard calibrations at preset time intervals (optional). Besides that, this model can be housed in a JIS- or EIA-compliant 19-inch rack.