Multi-core solder wire (60% tin, 40% lead). Suitable for fast soldering on copper or brass surfaces and solder-coated materials. Ideal for use on micro electronics, fine wires and most other electrical and electronic soldering operations. External diameter 1mm. Multi-core solder wire (60% tin, 40% lead). Suitable for fast soldering on copper or brass surfaces and solder-coated materials. Ideal for use on micro electronics, fine wires and most other electrical and electronic soldering operations. External diameter 1mm.