The CSD3 is a robust outdoor radiometer designed to measure sunshine duration, defined as periods when direct solar radiation exceeds 120 W/m². Using three precision photodiodes and advanced diffusers, it accurately detects sunny conditions without moving parts, providing a reliable digital output along with calculated direct irradiance values.

Built for long-term outdoor use, the instrument features a glass tube sensor, integrated drying cartridge with humidity indicator, and dual-level heating to prevent measurement disruption from rain, snow, or frost. It operates on a 12 V DC supply and includes a mounting arm for easy installation.

The CSD3 complies with international standards, including EMC Directive 2014/30/EU (CE), FCC Part 15 Class B (US), and ICES-003 Class B (Canada).