A disposable sheath device for use with an endoscope is disclosed. The endoscope has a body with an insertion tube having optics at its distal end. The disposable sheath device has a primary lumen and at least one secondary lumen attached to the primary lumen along a length of the lumen. The primary lumen is for covering and protecting the insertion tube from bodily contamination. The secondary lumen is for accommodating a desired tool. The secondary lumen has an insert substantially commensurate in length to the secondary lumen and has a slit longitudinally along its length. The slit permits radial expansion to accommodate tools having a radius larger than that of the secondary lumen, which preferably is made of a flexible material that expands. A connector is attached to the proximal end of the primary lumen and connects to the body of the endoscope. The connector extends longitudinally to accommodate different length insertion tubes. Optionally, an adapter can be used to attach the connector to the body of the endoscope. Varying the adapter permits the sheath device to be attached to various endoscope bodies.