"Compatible with single-lumen endotracheal tubes with an internal diameter of 5.0mm or greater; double-lumen tubes 37Fr. or greater. 1.5mm channel for easier aspiration/instillation of fluids. Olympus optical technology produces high-quality images for observation. Wider field of view (90°) for excellent visualization Insertion tube markers (bands) for quick determination of insertion depth. Waterproof for thorough reprocessing. "