UPS(C4H10N2O3S2) Chemical name: 3-S- thiuronium propyl sulfonate CAS.NO.: 21668-81-5 Appearance: white powder PH value: 1-4(5% aqueous solution) Melting point: 246癈 Level addition: 10-100(mg/l)Application: brightener for copper plating, and cooperate with polyethyldiol and anion surfactants. It can also be used for silver plating and palladium plating.