This object states which physical unit - deg-C(1) for temperature or milli-watts(2) for optical power - applies to all the current, minimum, maximum, and threshold objects for this transceiver sub-category row. An admin must read this value first before making sense of any of the sibling numeric objects, since the same table structure is reused for two entirely different kinds of transceiver measurement. For example, a row reporting XcvrHealthUnit of milli-watts(2) tells the admin that a XcvrHealthCurrMeasurement value of 1 represents received optical power, not a temperature.