This is a vintage Explorer prototype push dagger made in Seki, Japan by Seizo Imai circa 1980s. It features an integral design and comes with a molded sheath. Seizo Imai was one of Seki, Japan's finest craftsmen and most famous knifemakers of the modern era. His collaboration with Parker spanned nearly two decades. He made knives for Parker, Frost, Browning, Explorer, Compass, Condor, and many others, including his own brands Imax and Seizo Imai. His custom Loveless style knives are works of art. After his passing, several vintage old stock models were found at his warehouse. This is one of these rare finds.