Solder is used to create a conductive and strong connection between metals. The different types of solder wires can be identified by the diameter, the composition - i.e. which metals are contained in which proportion - and the flux type. In addition, solder is differentiated between hard solder and soft solder depending on the melting temperature. For soft solders, the melting temperature of the solder is below 450 °C, for hard solders it is higher.