The late Zhang Zhishun (张至顺also known as Mi Jingzi米晶子) demonstrates Jin Gang Gong (金刚功), a physical cultivation technique. In his video, Zhang is 97 years old. He died in 2015 at age 103. I had the good fortune to learn this form and another, Changshougong, in 2014 at Qianyuanguan on Maoshan.