The Hackman butterfly knife (Finnish: Linkkupuukko, "latch-knife") was a type of balisong (butterfly knife) produced by the Finnish company Hackman. The knife was marketed by Hackman as a retkiveitsi ("camping knife").
The knives were also sold in the United States, and some researchers state they were issued by the U.S. Central Intelligence Agency during the Vietnam War.
This knife is no longer produced, but similar models are offered by other Finnish companies.