A component of a rigid or flexible endoscope assembly designed as a tube through which an endoscope (e.g., hysteroscope) and endoscopic elements are introduced and assembled to create a complete operative endoscopic unit; it is also designed to function as a protective barrier to isolate the endoscope from patient contact and prevent contamination of the endoscope controls during a procedure. It typically contains ports to enable the insertion of instruments (through the endoscope or through independent working channels), insufflation ports, valves and connectors. It is made of plastic and metal materials. This is a single-use device.