This is a Spyderco/Vallotton design knife with the final customization done at the Vallotton shop. The Upper bolster slides back to launch the leaf spring hidden in the handle and thus firing out the blade.
Butch Vallotton, like most knife makers, started making knives as a hobby, had to start selling knives to pay for his hobby and before he knew it became a professional full time knife maker in 1984 with a waiting list of customers at the age of thirty. A self-proclaimed gadget freak, a good part of his business comes from automatic knives and he is credited with inventing the ambidextrous blade thumb stud.
His collaboration with Spyderco called the Vallotton Sub Hilt Folder features an ambidextrous thumb stud that both opens the blade (in addition to the Spyderco Round Hole) and doubles as a stop pin keeping the blade from rotating open beyond the locked position.
A long time fan of Italian-style, heavy-stock folders the Sub-Hilt bears an international flavor with a modified coffin-shaped handle of polished black G-10 with tongue-and-groove fitted stainless bolsters. Further complementing the handle is a Michael Walker LinerLock® a four-way: tip-up/tip-down, right- or left-handed steel clip and screw-together scale construction.
Crucible Steel Inc. of New York produces the CPM-S30V powdered steel used for the modified Tanto-shaped blade. The blade is hollow-ground at the cutting edge with a convex-grind at the tip and is offered in Plain Edged for the best available cutting performance.