Specifications: Take accurate alkaline/acid tests with this pack of 160 litmus paper strips. 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. Suitable for urine, saliva, drinking water, 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. Instructions: 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. Keep dry for the rest paper. Type: PH Test Paper Quantity: 2 Books Features: Indicator Paper, Universal, Full Range Package Size: 7cm x 4.5cm/2.76" x 1.77" (Approx.) Notes: Can not indicate the acid or alkali solution when its density was lower than 0.01%. Due to the light and screen setting difference, the items color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Included: 2 Books of PH Test Paper(160Strips)