It has the virtue of quickly coming up to soldering temperature (~300C) and delivering considerable heat to a small area, but requires care to avoid overheating.
The soldering iron's "element" is a small carbon tip at the end of a pushrod connected to one terminal of the power supply, inside the stainless-steel barrel of the tool, but insulated from it.
The original manufacturer, Scope Laboratories, of Melbourne, Australia, was a company founded in 1949 by two recent Czech immigrants, Richard Seligman[1] and Egon Jelinek.
At the suggestion of his wife, Lise, who also became a partner in the business, he and Jelinek, who was a mechanical engineer, designed and built the novel soldering iron[2] which heated up in a matter of seconds rather than minutes.
[9] The iron is still made and sold in Australia in its original (black handle) form, as well as an orange-handled version, dating from the 1970s, whose "sliding ring" also serves as a finger guard.