Development of reliable imaging polarimeters and the models that predict their performance is dependent on the ability to assess their accuracy. Field tests frequently result in contradictory data and laboratory measurements are often not representative of materials in the field. To address these concerns, we have built a device with which the calibration of imaging polarimeters (both stationary and moving) can be verified and the polarimetric properties of materials in the field can be measured with accuracy. The device is a handheld, non-imaging polarimeter that is capable of highly calibrated phenomenology measurements in both the lab and field. Multiple optical heads enable monitoring of samples from a variety of angles in order to characterize polarimetric signatures as a function of source, sample, and sensor geometry. The device may also be used in unattended diurnal monitoring of polarimetric signatures of the sky,
backgrounds, and targets of interest, providing a correlation between observed polarization phenomenology and weather conditions. The handheld device and the associated data acquisition system is small and portable enough that it can be taken to the field readily and is simple enough that calibration and system performance is predictable and verifiable. In this paper, we describe the design and performance of the non-imaging handheld polarimeter, performance specifications, and measurement results to date.