Abstract: A knife of the type having a blade which is selectively pivotally movable between extended and retracted positions relative to a handle. A rocker arm received between a pair of handle side portions is pivotally affixed thereto at the handle forward end and includes a locking member depending therefrom which is lockingly received in a knife blade locking notch when the blade is in the extended position. A leaf spring also disposed between the handle side portions acts against the rocker arm to continuously pivotally urge the locking member into engagement with the knife blade locking notch. The rocker arm extends axially outward from the rear of the handle side portions and has a pair of rear bolster members affixed thereto. These rear bolsters are selectively movable relative to the rear end edges of the handle side portions against the force of the leaf spring.