ORP tester|ORP Meter|ORP Pen SPECIFICATIONS: Range: -1999 to 1999mV Resolution: 1mV Accuracy : ±5 mV Batteries :4 x 1.5V alkaline Environment: 0 to 50°C,RH 95% max; Dimensions :175x41x23mm Weight :72g OPERATION @Remove the protective cap. Do not be alarmed if white crystals appear around the cap. This is normal with ORP electrodes and they dissolve when rinsed with water. @Turn the meter on sliding the switch on the top. @Immerse into solution up to the max immersion level. @Stir gently and wait until the display stabilizes. @After use, switch off ORP meter,, use the water clean the electrode and replace the protective cap. Do not use distilled or deionized water for storage purposes. @Large fluctuations in readings could be due to lack of calibration, dry electrode or rundown batteries. Attention :during 2-3 weeks, put electrodes in 3mol/L KCL solution for 12 hours, to make sure the reading within accuracy. BATTERY REPLACEMENT If calibration can not be performed or the display fades, batteries must be replaced. Slide off the battery compartment cover and replace all four 1.5V alkaline batteries, while paying attention to the correct polarity. Batteries should only be replaced in a non-hazardous area and using the battery type specified in this instruction manual. WARRANTY These instruments are warranted from all defects in material and manufacturing for a period of one year from the date of purchase.If during this period, the repair or the replacement of parts is required where the damage is not due to negligence or erroneous operation by user, please return the parts to either dealer or our offices, and the repair will be effected free of charge