Features 【HIGH PRECISION INSTRUMENT】This meter is a precision instrument measuring the intensity of sunlight. Large LCD display, 4-1/2 LCD display, maximum 19999. High resolution, wide measurement range and short sampling time. 【STANDARD PARAMETER】There are two units that can be selected: W/m² and Btu. Our SM206 sun light energy measuring tester features direct measurement without adjustment, long-term stable measurement. 【DATA RETENTION】It supports maximum value hold function and data hold function.This professional solar radiation meter panel is designed with a “HOLD” button that supports maximum hold and data hold, which is simple and convenient for recording user-friendly data comparison and experimental investigation 【DIRECT MEASUREMENT】Measure directly without adjustment, steadily measure for a long period. Pay attention to the automatic measurement of the probe directly to the light source, and keep the probe clean to avoid affecting the measurement results 【WIDELY APPLICATION】Widely used for solar radiation measurement, solar energy research, meteorology, agriculture, physical and optical experiments. It can also be used to measure the light transmission intensity of glass to verify the performance of the glass, for example, car window performance test. Specification: Model: SM206 Resolution: 0.1W/m², 0.1Btu/(ft²-h) Range Error: ± (10%R+2dgts)R: readings Temperature Error: ±0.38W/m²/℃[±0.12Btu/(ft²-h)/℃] deviation at 25°C  Display: 4-1/2 LCD display, maximum display numerical value 19999 Overload Display: "OL" Shift: <±1.5% /year Measurement Range: 0.1-1999.9W/m², 0.1-1999.9Btu/(ft²-h) Sampling Time: 0.25 seconds/time Operating Temperature and Humidity: 0~50℃,  <80%RH Storage Temperature and Humidity: -10~60℃, <70%RH Battery: 9V battery (NOT included) Size: Approx. 132 x 60 x 38mm / 5.2 x 2.4 x 1.5in Weight: 325g / 11.5oz (approx.) Package list: 1 * Solar Radiation Measuring Instrument (battery is NOT included) 1 * User Manual 1 * Packing Box  Package List 1 * Solar Radiation Measuring Instrument (battery is NOT included) 1 * User Manual 1 * Packing Box