To prove the functionality of PFC-free clothing, Deng Lin, Icey Tsui and A.M., 3 outdoor key opinion leaders from Mainland China, Taiwan and Hong Kong respectively summited one of the peak Da Feng of the Four Sister
Mountains (5025m) located in Sichuan, Mainland China in January 2016. Under the cold current with -20 degree celsius, the climbers spent 4 days on the mountain and summited Peak Da Feng.