This probe is the same as the HMP35C3, except the customer could order custom cable lengths. The HMP35C3-L used a HUMICAP H-sensor to measure relative humidity and a thermistor to measure temperature. It contained a switching circuit to conserve system power. A solar radiation shield was required if the probe was exposed to direct sunlight.
The "-L" on a product model indicates that the cable length is specified at the time of order.