This is RS485 signal transmission line, made of pure Cu (copper) which is of excellent quality. Little signal attenuation, it has better performance compared with other signal lines which is made of twisted synthetic brass wires.
Of widely use, it can be accessory for devices support RS485 function.
Moreover, it can be also customized. If you need one longer than 5 meters, the extra length (above 5 meters), it costs USD 1.2 per meter. For example, if you need a 7m line, it would cost you USD 9.4 (5m line: USD 7 + extra 2 meters: USD 1.2*2)