In 2016, construction was completed for two custom ultra-portable visible and near-infrared (VNIR) transfer radiometers developed by the Remote Sensing Group (RSG) at the University of Arizona. Dubbed CaTSSITTR (Calibration Test Site SI-Traceable Transfer Radiometer), these instruments have since been used for transfer radiometry in support of various field and laboratory calibrations around the world, much in support of the Radiometric Calibration Network, or RadCalNet, an initiative of the Working Group on Calibration and Validation of the Committee on Earth Observation Satellites (CEOS).As technology advancements in short-wave infrared (SWIR) detectors have matured and become more commercially available, RSG has been testing these SWIR detectors and system components towards the end goal of producing SWIR transfer radiometers based on similar design goals as the CaTSSITTRs. These goals include one operator portability and data collection, and standalone (battery) power for field collection times. To this end we strive to prove we can achieve high accuracy transfer radiometry in the SWIR without liquid nitrogen cooling or optical chopping. This work details the prototype testing results and system design details of these new SWIR ultra-portable transfer radiometers.