311 is a highly effective anti-discoloration agent for silver plating in the communication electronics industry. It can be applied to the high-temperature anti-discoloration test at 280 degrees for 10 minutes when the plating is copper (6μm) and silver (1μm). At the same time, it can withstand the 5% K2S test for 5 minutes without discoloration (under 25℃ conditions, the time is related to the thickness of the silver plating); for gold plating, it has no corrosion in a 72-hour salt spray test.