ORIGINAL SUNLIGHT USB QUANTUM SENSOR - Designed by world-renowned crop physiologist, Bruce Bugbee, PhD, the Apogee SQ-420X USB smart quantum sensor features Apogee's older and more economical photodetector that is excellent for measuring photosynthetically active radiation (PAR) accurately under sunlight, metal halide, and high-pressure sodium lights. For measuring other light sources, including LEDs, we recommend using our newer full-spectrum or ePAR sensors.

FOR SCIENTISTS & SERIOUS GROWERS - Unlike cheaper LUX or footcandle sensors which are sometimes marketed as grow light meters, but are meant for measuring light for human vision, our sensors feature a laboratory-grade photosynthetic photon flux density (PPFD) optical detector precisely calibrated to measure the light intensity in µmol m-2 s-1 of the specific color wavelengths emitted by sunlight, MH, and HPS lights that are used by plants for photosynthesis.

USB COMPATIBLE - Smart quantum sensor can be connected directly to a computer (Windows or macOS X) for taking spot measurements or graphing and datalogging real-time PPFD using the included ApogeeAMS software. The sensor can also act as a stand-alone PAR datalogger by simply connecting it to most standard 5 V DC USB power plugs.