Description: It has a temperature automatic compensation function that the water temperature will not affect the results, and you can understand the PH of different waters. It has fast readings and accurate data, which makes it very reliable. You don't need to pass complicated chemical experiments, just use it to test, you can know the PH of the water. Made of ABS material, it is durable to use. The length of the yellow one is 15.5cm and the width is 3cm. The length of the green one is 15.5cm, the width is 3.1cm and the height is 1.8cm. It is suitable for water, aquarium, swimming pool, and so on. Item Name: PH Test Pen Material: ABS Batteries: 1.5V (LR44 Button Battery), Yellow: 4pcs, Green: 2pcs (Included) Operating Temperature: Yellow: 0-50 Degree Celsius, Green: 0-80 Degree Celsius Measuring Range: 0.00-14.00PH Color: Yellow, Green Resolution: 0.01PH Accuracy: 0.01PH Calibration Method: CAL Automatic Calibration Size Details: Size: Yellow: 15.5cm x 3cm/6.1" x 1.2" (Approx.) Green: 15.5cm x 3.1cm x 1.8cm/6.1" x 1.2" x 0.7" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Yellow PH Meter 2 x 250ml Calibration Solution Powder 1 x Screwdriver 4 x Batteries 1 x English User Manual or 1 x Green PH Meter 3 x 250ml Calibration Solution Powder 2 x Batteries 1 x English User Manual