NGC PF70 UC China 60g (60 Grams) Solid Silver Medal - Longmen Grottoes (Struck by Shenzhen Guobao Mint). Condition: S/N might be different from the listing. Welcome to Giant Panda Coins! Our antique store has over 12 years old history. Flagship store locates at Yun-Zhou commercial building, Shanghai, China.Branch store locates at Ju-Qi-Cheng commercial building, Shanghai, China. We speak English and some German.