procurement of colorimeter for chlorine testing ( re-invited , instrument with following specification: optics leds, 3 interference filters ( if ) and photo sensor in transparent sample chamber. wavelength specifications of interference filters: ? ? = 5 nm wavelength selection automatic wavelength 530 nm = 5 nm 560 nm = 5 nm parameters facility chlorine and ph as an additional option measuring range: chlorine hr tablet: 0.1 - 10 mg / l cl2 dpd, chlorine liquid / powder: 0.02 - 4 mg / l cl2 dpd, chlorine tablet: 0.01 - 6 mg / l cl2 dpd, ph value l 6.5 - 8.4 phenol red, ph-value t 6.5 - 8.4 phenol red wavelength accuracy ± 1 nm photometric accuracy 3% fs ( at 20°c - 25°c ) power supply 4 micro batteries ( aaa ) , capacity approx. 17 hours or 5000 tests auto – off yes display backlit lcd ( on keypress ) data storage internal memory minimum 100 bluetooth interfaces yes calibration factory calibration and user calibration. protection class ip 68 environmental conditions temperature: 5 - 40 °c rel. humidity: 30 -90% ( non-condensing ) pc software it will be supplied with pc software to import data directly from the photometer to the windows-based pc. additional accessory bluetooth dongle compatible with photometer , ( make: djb approved make )