Resolution 0.1 µmol mˉ² sˉ¹ Calibration Factor Custom for each sensor and stored in the firmware Calibration Uncertainty ± 5 % Measurement Repeatability Less than 1 % up to 4000 µmol mˉ² sˉ¹ Long-term Drift Less than 2 % per year Non-linearity Less than 1 % (up to 4000 µmol mˉ² sˉ¹) Response Time Software updates every second Field of View 180˚ Spectral Range 389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 % of maximum) Spectral Selectivity Less than 10 % from 412 to 682 nm ± 5 nm Directional (Cosine) Response ± 2 % at 45 ˚, ± 5 % at 75 ˚ Azimuth Error Less than 0.5 % Tilt Error Less than 0.5 % Temperature Response -0.11 ± 0.04 % Cˉ¹ Uncertainty in Daily Total Less than 5 % Detector Blue-enhanced silicon photodiode Housing Anodized aluminum body with acrylic diffuser IP Rating IP68 Operating Environment -40 to 70 C; 0 to 100 % relative humidity; can be submerged to depths of 30 m Dimensions 24 mm diameter, 37 mm height USB Cable 4.5 m (15 ft) Mass 100 g (with 5 m of lead wire) Current Draw 61 mA Warranty 4 years against defects in materials and workmanship