Monitor visible light levels anywhere with fast, stable and accurate response. Results are easily read on the extra large LCD (1 1/2" high, 38.1 mm) with bar graph, low battery and over range indications Light Meter Lux/FC Sper Scientific 840020 Fast, stable and accurate response Monitor visible light levels anywhere with fast, stable and accurate response. Results are easily read on the extra large LCD (1 1/2" high, 38.1 mm) with bar graph, low battery and over range indications. The color and cosine corrected sensor meets C.I.E. photopic spectrum. Also features RS232 computer output, min/max, auto power off, external zero adjustment, hold function and a tripod back. The lux / footcandle light meter comes ready to use with a 9V battery, instructions, soft padded case with shoulder strap, and a detachable sensor (with 44" cord) with cover for easier replacement or repair. N.I.S.T. traceable certificate of calibration available. Meter Dimensions: 8" x 2 ¾" x 1 ¼" (200 x 68 x 30 mm) Weight: 9 oz (280 g) Specifications: Range Resolution Accuracy Light Meter Lux 840006 20,000 lux 1 / 10 lux ±(5% + 4d) Light Meter FC 840021 2,000 fc 0.1 / 1 fc ±(5% + 4d) Light Meter Lux/FC 840020 400,000 lux 0.01 / 1 lux ±(3% + 0.5% fs) Advanced Light Meter 840022 40,000 fc 0.001/1 fc 840020 Light meter Lux meter SPER Scientific à¤Ã×èͧÇÑ´áʧ