The Solder Rosin Core - Standard 1 lb spool features a composition of 10% tin and 90% lead, making it suitable for general use in electrical soldering. With a convenient 1/8 diameter, this solder provides excellent flow and adhesion for reliable connections. Its rosin core ensures a clean and effective soldering process, making it a preferred choice for professionals in the automotive and industrial sectors. Ideal for various electrical applications, this product comes in a manageable 1-pound spool for ease of use.