the wound retractor consists of four parts: green ring, retraction sleeve, blue ring , and attachment ring. two flexible plastic rings are connected by a flexible and clear retraction sleeve. the diameter of the green ring is the same as the blue ring and sleeve. the ring's semi-circular configuration creates a torsional force to maintain desired wound dilation once installed. this is a single-use and sterile device. the device is intended for short term use and is a surgically invasive device.