Oman. Silver Proof Set of 2 1/2 and 5 Rials 1977, World Wildlife Conservation, Caracal (Silver 38,61 mm, weight 28,28 g. .925) and Arabian White Oryx (Silver 42 mm, weight 35 g. .925), KM 60, 61, Condition Proof, original box and certificates, slight tarnish - patina, small spots, photo taken through the plastic in the cap