These four buttons will help you quickly hide and unhide various parts of the hand system.
Hides and Unhides the blending fingers that are usually displayed in the viewport.
Hides and Unhides the forward kinematic fingers that controlled via the rotation spinners.
Hides and Unhides the inverse kinematic fingers that controlled via the finger IK targets.
Hides and Unhides the inverse kinematic finger targets. The positions of these objects can be animated by moving them in the viewport or by hitting the appropriate SnapIK or green/blue 'X' buttons that bring them to the finger tips.