There is a strong correlation between the pH of the body's internal environment and pH paper help you to maintain good healthy body by testing many usual everyday substances, including moisturized soap, lemon juice, milk, liquid detergent, moisturized soil, saliva, urine, sweat...etc The scale reads from 1 to 14: 1 - 3 indicates a very acidic substance 4 - 6 indicates an acidic substance 7 indicates neutral 8 - 11 indicates alkalinity 12 - 14 indicates a very high level of alkalinity PH 1-14 color chart in each pack The test strip color changes must be matched with the pH scale color chart within about 15 seconds Paper Size: app 45mm x 7mm (L x W) Instruction: 1.Simply press the testing strip to the object or liquid you are testing. Half second later, take out the paper and using the color chart included, compare the color change of the paper to find out the acidity level of your testing subject. 2.Can not indicate the Acid or alkali solution when its density was lower than 0.01%. 3.Keep dry for the rest paper Package included: 1set=80 Strips pH test paper Hello, dear friend: Since your feedback is very important to our business`s development, we sincerely invite you to leave positive feedback for us if you are satisfied with our product and service. It`ll just take you 1 minute. Thank you! _x000D_