Sper Scientific Ltd. Test Tube pH Pen is designed for easy calibration and simple, accurate measurement. The 12 cm long probe is capable of testing samples even in narrow-mouthed containers. The waterproof meter provides one-button, three-point calibration with customizable calibration values. Other features include a data-hold function, automatic shutoff and low-battery indicator. This model also measures temperature and provides automatic temperature compensation Shipping Details Shipping Type: parcel Free Shipping: true Specifications Maximum Age: 12 years Resolution: 0.01 UPC: 816366023436 Allergens: Contains No Allergens Certifications: Not Applicable Grade Level: High School-College SUOM Description: Each Accuracy: 0.2 Brand Name: Sper Scientific Ltd Description: Test Tube pH Pen Display Type: LCD Material: Plastic Model Number: 850062 Number Of Batteries: 2 Material Type: Plastic