Refined Parts S are common materials in Xenoblade Chronicles. They can be traded for with Kazat or obtained from various Mechon. During the two battle event of the Galahad Fortress, the two Defensive Guard Unit variants, the two M94 Guard Unit variants as well as Face Nemesis and Gold Face do not drop any chests but the Refined Parts S they carry can only be obtained by using Riki's Yoink! ability.