Review on Litmus Universal Application Indicator Testing: Measure compatibility across various applications by Carlos Reyes

I bought these for a chemistry experiment and they suck! These are normal papers! The paper color never changes! What a scam! that's awful! DO NOT buy this! I have tested shampoo, vinegar, water and urine on them and they DO NOT WORK! And they delivered in a week when they were supposed to come in 2 days! The instructions are in Chinese, the package cannot be opened. Not to mention it's the size of half a palm!