allow simultaneous ventilation and gastroscopy,fiberoptic bronchoscopy or fiberoptic intubation endoscopy mask. ... . is 15mm1200Products Advantages:1.Allow simultaneous ventilation and gastroscopy, fiberoptic bronchoscopy or fiberoptic intubation.2.Excellent transparency shell ... of the doctor. allow simultaneous ventilation and gastroscopy,fiberoptic bronchoscopy or fiberoptic intubation endoscopy mask