Buck PARADIGM Model 591 "Shift" Auto Bolster Release Auto with Black G-10 and S35VN Stainless 

The Paradigm "Shift automatic knife" or Bolster Release opens by sliding the Top Bolster forward (or to the side depending on how your are holding the knife), which activates the spring and opens the blade automatically.  The Black Cerakote® coated Stainless bolster slides back down on it's own and locks the blade in the open position. Accented with a gold tone pivot and back spring , the Paradigm Shift features a 3 1/4" Satin Finished Spear Point Blade made from premium S35VN stainless  with Non-Slip Black G10 handles and black stainless liners

A Cerakote coated black pocket clip allows for easy carry, and the bolster lock prevents accidental deployment. It closes the same way as opening- by sliding the bolster open (upward) to unlock the blade. Lock it closed by sliding the bolster back in place. (Operates similar to Protech's MAGIC Auto Knife, but you have to slide the bolster further up on the Buck. Includes a very nice presentation case/storage box. Just arrived from Buck.  Measures 4 1/2" closed. Made in the USA.