1980年加厚黃銅精製套幣。奧林匹克系列。四枚一組。发行量:2,000(每款)。1) NGC PROOF-68 Cameo。KM-P7。高山滑雪。2) NGC PROOF-68 Ultra Cameo。KM-P8。速度滑冰。3) NGC PROOF-68 Ultra Cameo。KM-P9。花样滑冰。4) NGC PROOF-68 Cameo。KM-P10。冬季两项。闪耀非常,铸打於厚坯上。CHINA. Brass Piefort Yuan Proof Set (4 Pieces), 1980. Olympic Series. All NGC PROOF-68.Mintage: 2,000 (for each type).1) NGC PROOF-68 Cameo. KM-P7. Alpine Skiing.2) NGC PROOF-68 Ultra Cameo. KM-P8. Speed Skating.3) NGC PROOF-68 Ultra Cameo. KM-P9. Figure Skating.4) NGC PROOF-68 Cameo. KM-P10. Biathlon.A dazzling and brilliant offering struck on extra thick planchets.