Description:   Pocket Digital Tester Meter Pen LCD Monitor Aquarium Pool Water Measuring Tool   Features:    1. Measuring pH Range: 0.0 - 14.0 pH 2. Resolution: 0.01 pH 3. Accuracy: ±0.1 pH (20 C) 4. Operating Temperature: 0 - 50 C (32 - 122 F) 5. Battery: 4*1.5V(AG-13) 6. Dimensions: 150 x 30 x 16mm 7. This digital pen style pH meter is an ideal instrument for aquarium、 fishing industry、 swimming pool、school laboratory、 food & beverage etc. Very excellent、 accurate and durable                             Package includes:    1 x Digital pH meter 1 x Calibration Adjustment Screwdriver 1 x User instruction (English) 1x PH buffer powder   Details pictures: