VERZONE Crystal#120, a Benzotriazole (BTA) compound (C6H5N3, MW 119.12), is a highly effective water-soluble rust preventing agent for copper and copper alloys. This white needle crystal, with a melting point of 96°C and over 99.0% purity (pH 5.5 at 1%), provides strong rust prevention by forming a thin film (<1µm) even with small additions. It demonstrates excellent stability against acids and alkalis, good solubility, and low toxicity. Its applications include water-soluble cutting oils, nonflammable actuation liquids, anti-freeze liquids, and recirculating cooling water, typically added at 0.1-2.0% in water treatment agents, metalworking fluids, and cleaners.