The KFV 2 Hooks & 2 Rollers Split Spindle 35mm has 2 hooks and 2 rollers. It is important to note that this lock will not accept a single spindle as it is strictly for use with a split spindle. Handing can be changed by reversing the latch. The hole in the side of case adjacent to the latch contains a small screw. Depending on which side the function is set, turn the screw clockwise or anti clockwise until it stops to reverse the nightlatch function.