Specifications Hign-concerned Chemical:None Is Smart Device:No With Backlight Or Not:Yes Brand Name:JUANJUAN Origin:Mainland China Display Type:Digital Name:Chlorine Testing Pen Battery:3*1.5V(LR44) (Not included) Waterproof class:IP65 Working environment:0-60C(32.0-140.0F) RH: 100% Backlight:LCD screen backlit display Automatic shutdown:Five minutes Screen size:28*20mm Display mode:Liquid crystaldigital display Digital Residual Chlorine Tester Multifunction Water Quality Tester 2/3/4/5 in 1 CL2 TEMP pH H2 ORP Meter Pool Water Testing Pen Parameter: pH Measuring range: 0~14.00pH Resolution: 0.01 pH Accuracy: 0.01pH Temperature compensation: 0~60(Auto) ORP Measuring range: 1999mV Resolution: 1mV Accuracy: 2mV CL2 Measuring range: 0.01~4.00ppm (Total residual chlorine) Resolution: 0.01ppm Accuracy: 10% reading value, 0.01ppm Temperature compensation: 0~60(Auto) H2 Measuring range: 0~10000ppb (0.001~10.000ppb) Resolution: 2ppb (0.002ppb) Accuracy: 10ppb (0.01ppb) Temperature compensation: 0~60(Auto) TEMP Measuring range: 0~60 Resolution: 0.1 Accuracy: 0.1 2 in 1 CL TEMP Testing Pen 3 in 1 CL H2 TEMP Testing Pen 4 in 1