Usage Tips:Features:Measuring range: 0-4000ppb /0-4.000ppm, resolution 1ppb/0.001ppm.High precision hydrogen meter with high sensitivity probe. with backlight, data hold function.Easy to operate,carry. Easy to change electrode. ATC symbol indicates that the instrument is in automatic temperature compensation mode.IP67 is an international waterproof and dustproof certification. for Protection against dust intrusion, short-time immersion.for Ideal for testing water, swimming pools, aquariums, spas, hydroponics, laboratory, and drinking water, etc. Specifications:Material: ABSSize: 183x37mm/7.2x1.46inButton battery: included Note:Please allow 1-3cm error due to manual measurement. pls make sure you do not mind before you bid.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes:1x Hydrogen Meter