Negara Brunei Darussalam, Proof Coin Set, 1991 [6], $1-1 Sen, in silver, Singapore Mint brilliant uncirculated, scarce with only 2,000 sets issued, in mint case of issue, with certificate of authenticity no. 0984; additionally, silver Proof-10 Dollars, 1977, 10th Anniversary of Brunei Currency Board (KM 21), brilliant uncirculated [7].