A tubular device intended to be used in combination with a compatible flexible endoscope to aid in endoscopic insertions and to secure a pathway for multiple endoscopic intubations during diagnostic and therapeutic endoscopic procedures (e.g., upper and/or lower gastrointestinal (GI) tract endoscopy). It is a non-steerable, typically single lumen tube constructed of plastic; some types may be "shape locked" into a desired configuration or form to assist in the repeated advancement and withdrawal of the endoscope (e.g., for the removal of multiple polyps and/or foreign bodies). This is a reusable device.