HX-T100 MECHANIC 0.4mm Solder Wire , which is a type of fusible alloy that is used to join metal parts together. Composition: It is made of tin (Sn) and lead (Pb), with a typical ratio of 63% tin and 37% lead. It also contains flux, which helps to clean the metal surfaces and improve the solder flow. Melting Point: It has a low melting point of about 180-190°C, which makes it easy to work with. Electrical Conductivity: Solder wire conducts electricity, which is necessary to create strong connections between electrical components.