One of my favorite Spyderco designs is their Caly 3.5. This knife, in my opinion, is one of the most elegant modern knives. Spyderco recently released a Sprint Run version of this knife...sporting Carbon Fiber handle scales and a ZDP-189/420-J-2 blade. This knife features a lockback (mid lock) system. Normally, this locking system keeps knives from opening as smoothly as the Ball Lock and Axis Lock mechanisms. Oddly, this Caly 3.5 opens SUPER SMOOTH.