A knife includes a blade and a handle assembly rotatably coupled to the blade, defining a longitudinal axis, and including a side frame, a handle frame spaced apart from the side frame, a locking arm coupled to the side frame and angularly movable relative to the longitudinal axis between a locked position and an unlocked position, the locking arm defined by an arm width, and a guard coupled to the side frame and overlaying at least a portion of the locking arm, the guard being defined by a guard width measured in a direction perpendicular to the longitudinal axis, the guard width being a distance between a bottom side of the guard and a top side of the locking arm, wherein a ratio of the guard width to the arm width at any given position along a length of the guard is greater than thirty percent.