The Ferris-Smith Sewell Orbital Retractor (39x11mm) is a specialized surgical instrument used in ocular and orbital surgeries. The 39x11mm dimensions refer to the size of the retractor blade, which is designed to provide adequate exposure of the orbital cavity during surgical procedures. The orbital retractor helps retract the eyelid or tissues around the eye, providing the surgeon with clear access to the delicate structures in the orbital area.