Watch List notes:

OMAN: Qaboos bin Said, 1970-2020, 6-coin proof set, 1990/AH1411, KM-PS5, includes 5, 10, 25, 50, 100 baisa and sterling silver 2 rials, all commemorating the 20th National Day in Oman, in the original British Royal Mint case of issue with COA, mintage of only 3,200 sets, set of 6 coins, S.

Estimate: 150-250 USD