The CS241 is the next generation of Campbell Scientific back-of-module temperature sensors with new features designed for bifacial photovoltaic (PV) module performance assessment and soiling. The probe head has been redesigned for easier installation. The measurement performance has been improved with a smaller footprint that is optimized to reduce back-of-module shading and eliminate surface cooling. Other improvements include greater sensor-to-module bonding/adhesion and a thinner Teflon cable with a higher temperature rating. To meet the requirements of performance validation, every CS241 is supplied with a NIST-traceable, serialized calibration certificate. The CS241 is a surface-mountable PRT that measures back-of-module temperature for solar PV applications. It uses a precision PT-1000 Class A PRT to provide the highest level of accuracy. The CS241 improves back-of-module temperature-sensor quality with a smaller profile sensor head and cable, greater sensor-to-module bonding/adhesion, and higher temperature rating. This sensor has a small footprint and rugged design, making it proficient at measuring bifacial PV module temperature and allows optimum power production. An adhesive tab on the disk fastens the sensor to the measurement surface. The disk promotes heat transfer from the surface and protects the PRT, particularly during installation. The CS241 provides PV stakeholders with accurate back-of-module temperature, even at long cable lengths, for use in power performance modeling and simulation of solar energy applications.-->