Features SOLAR METER: Two units of W/m2 and Btu are available; 4-1/2 digits digital display; support maximum hold function and data hold function; direct measurement without adjustment; long-term stable measurement. PARAMETERS: Resolution: 0.1W/m2, 0.1Btu/(ft2-h); Range error: ±10W/m2 (±3Btu/(ft2-h) or ±5% of the measured value; Temperature error: ±0.38W/m2/ ℃ ±0.12Btu/(ft2-h)/℃ Deviation at 25°C; Display: 3-3/4 LCD display, maximum 3999; Measuring range: 0.1-399.9W/m2, 1-3999W/m2, 0.1-399.9Btu/(ft2-h), 1-3999Btu/(ft2-h) PACKAGE: 1 * Solar radiation meter (without battery); 1 * User manual; 1 * Packing box. EASY OPERATION: Measure directly without adjustment, steadily measure for a long period. 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: 2.5 seconds/time Operating Temperature and Humidity: 0~40℃,  <80%RH Storage Temperature and Humidity: -10~50℃, <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