an a pocket knife with moving parts match the absolute reliability of a solid fixed blade while staying compact in your pocket?
Zyac Design’s Z01S tries to end that debate by acting as a hybrid. The Z01S is a folding knife built from Grade 5 titanium with a sliding handle that you can shorten while the blade remains open. Transformingarmos the handle engages a secondary lock meant to prevent accidental closure. In practical terms, this mechanism offers two distinct grip lengths on a single tool. In our view, while this dual locking system is a clever mechanical exercise, it remains an expensive novelty built primarily for mechanical knife enthusiasts.
How the Sliding Grip and Double Lock Work
Earlier models from Zyac Design, including the original Z01 and the later Z05, incorporated sliding components to squeeze more cutting edge into a smaller frame, with the Z05 getting close to a 1:1 blade-to-handle ratio on a compact frame. The Z01S takes that approach further by letting you actively adjust handle length without needing tools, loose parts, or screws. With the blade open, you press a release button, slide the rear section of the handle forward, and it locks into its shorter position.
"A standard liner lock holds the blade open in either mode, while a second lock engages when you shorten the handle."
According to Zyac Design, this second interlock prevents the blade from folding while the handle is shortened, even if the primary liner lock is released. Folding the knife back requires a deliberate sequence: you must extend the handle first, then disengage the liner. What prevents the mechanism from shifting inside your pocket?
Zyac Design states that the release button cannot be pressed while the knife is closed, which stops the handle from sliding into the blade edge during carry. In fact, despite the complex sliding frame, the knife does not use removable parts to switch modes.
Exposed Hardware and Premium Materials
The standard Z01S handle is machined from Grade 5 titanium, an alloy of titanium with aluminum and vanadium that adds strength over pure titanium without extra weight, finished with a stonewashed surface to disguise scuffs. The blade uses Böhler M390 powder metallurgy steel, which contains chromium, vanadium, and molybdenum, and comes in either a drop point or a tanto profile. Each side of the handle includes three slots designed for tritium or photoluminescent tubes measuring roughly 0.06 x 0.24 inch, creating six slots total.
"Collectors get three premium editions beyond the standard titanium model: black zirconium with a gold titanium frame, full black zirconium, and a ZircuTi frame paired with a Damascus blade."
ZircuTi is a layered laminate of titanium and zirconium that provides a distinct striped look across the handle. The Z01S ships without a pocket clip, using a lanyard hole and knife bead instead, though an optional clip can replace the middle spine piece.
Zyac Design lists the standard knife purchase price at $379, marked down from $499 with 5 of 50 units remaining, while Kickstarter pledges for the Z01S start at $299. Complex moving joints simply cannot replace the structural peace of mind of a solid fixed blade during heavy cutting tasks. For anyone needing a dependable daily work tool rather than a collector's mechanical showcase, spending nearly four hundred dollars on sliding titanium scales is hard to justify.
What it signals
Does an intricate sliding mechanism justify its place in a practical everyday pocket tool? Zyac Design created an unconventional folding hybrid with on-the-fly handle adjustments, yet adding moving sections naturally compromises the structural simplicity needed for tough daily tasks. Premium Grade 5 titanium and Böhler M390 steel give the build top-tier materials, but the complex multi-lock system ultimately turns the device into a collectible mechanical showpiece rather than an unpretentious workhorse. A $299 Kickstarter tier running up to the $379 standard retail tag firmly places this transforming folder into luxury gadget territory.