Red litmus paper is a base indicator. It turns blue at 8.1 pH and higher. While not a measure of pH levels, it's a quick and accurate way to determine if a solution is alkaline.
LITMUS RED INDICATOR PAPERS
Oman, Bahrain, Abu Dhabi, Ajman, Al Ain, Dubai, Ras Al-Khaimah, Fujairah, Sharjah, Umm Al Quwain, Ruwais, Khalifa Port, Jebel Ali, DP WORLD, and all UAE ports...