Product description Spad 502 Plus Chlorophyll Meter can quickly measure chlorophyll content or “greenness” of different plants to reduce the risk of yield-limiting deficiencies or costly overfertilizing. This Chlorophyll Meter quantifies small changes or trends in plant health long before being visible to the human eye. Non-invasive measurement.Measured datum will be displayed in trend graph. It can be used to enhance the utilization rate of nitrogen fertilizer. Technical parameters Measuring mode: 2 wavelengths optical density difference Measuring area: 2 mm×3 mm Sensor: Silicon semiconductor photodiode Display mode: LCD, 4 decimal places, tendency chart Measuring range: -9.9 to 199.9 SPAD units Memory capacity: 30datum, automatically calculate and display average value Power: 2 AA batteries (1.5V) Battery life: More than 20,000 times Test interval: 2s Accuracy: Within ±1.0 SPAD units (for SPAD value between 0 and 50 under normal temperature) Repeatability: Within ±0.3 SPAD units (for SPAD value between 0 and 50) Reproducibility: Within ±0.5 SPAD units (for SPAD value between 0 and 50) Working environment: 0-50°C Other functions: alarm; calibration Weight: 255G Size: 164*78*49CM