The Spyderco Endura 4 Knife has the Emerson wave opening feature. This model has screw construction making cleaning and adjusting easier. The fiberglass reinforced nylon handle comes molded with Bi-Directional Texturing® for preferred traction and improved ergonomics. Inside the handle dual skeletonized stainless steel liners make the knife stronger without adding weight and make an anchor for all external and internal components to attach through adding sturdiness and rigidity.