High quality There is a strong correlation between the pH of the body's internal environment and pH paper can help you maintain a healthy body by testing common everyday substances, including moisturized soap, lemon juice, milk, liquid detergent, moisturized soil, saliva, urine, sweat, etc. Original box: no Item size: 70 x 44 x 4 mm 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 included in each pack. The test strip color change must be matched with the pH scale color chart within about 15 seconds. Paper size: 59 mm x 8 mm. Simply press the testing strip to the object or liquid you are testing. Half a second later, remove the paper and, using the included color chart, compare the color change of the paper to determine the acidity level of your test subject. Cannot detect acid or solution when its concentration is lower than 0.01%. Keep the remaining paper dry. Net weight: 8 g Package contents: 1 pack pH test paper Only the above package content is included; other products are not included. Note: Lighting and different displays may cause the color of the item in the picture to differ slightly from the actual item. Measurement error allowance is +/- 1–3 cm.