[. . . ] TDS1 TDS Meter with Automatic Temperature Compensation SPECIFICATIONS Range 0 to 999 ppm (mg/L) Resolution 1 ppm Accuracy (@20°C/68°F) ±2% f. s. [. . . ] Pull out the batteries compartment as shown in the drawing, and replace all four 1. 5V 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. Recommendations for users Before using these products, make sure that they are entirely suitable for the environment in which they are used. Operation of these instruments in residential areas could cause interference to radio and TV equipment. Any variation introduced by the user to the supplied equipment may degrade the instrument's EMC performance. To avoid electrical shock, do not use this instrument when voltages at the measurement surface exceed 24 Vac or 60 Vdc. To avoid damage or burns, do not perform any measurement in microwave ovens. WARRANTY This meter is guaranteed for six months against defects in workmanship and materials when used for its intended purpose and maintained according to instructions. Damages due to accident, misuse, tampering or lack of prescribed maintenance are not covered. [. . . ] When shipping any instrument, make sure it is properly packaged for complete protection. [. . . ]