The pH meter measures the difference in electrical potential between a pH electrode and a reference electrode, and so the pH meter is sometimes referred to as a "potentiometric pH meter ". The difference in electrical potential relates to the acidity or pH of the solution. Features: Quick and accurate pH readings Clear digital display screen Easy one-button operation Lightweight and portable design Durable body for long-term use Specification: Measure range: 0.00- 16.00PH Resolution: 0.01PH Accuracy: ±2% Power Supply: 2*1.5V Operating Temperature: 0°C - 60°C / 32°F - 140°F Dimension: 155mm* 31mm * 18mm / 6.1" × 1.2" × 0.7" Weight: 50g / 1.76oz Uses: Aquariums and Fishkeeping Hydroponics and Indoor Gardening Swimming Pools and Spas Testing Drinking Water / RO Systems Home Brewing and Food Production Package Includes: 1 x Digital pH Meter, Water PH Test Meter