1) Equipped with two radiopaque marks, easy to observe under X-ray. 2) Precise balloon size, each specification refers to only one balloon diameter. 3) Various balloon size for choose, meets different clinical demand. 4) After triplicate-wings folding, pass through 2.8mm working channel easily; safe and convenient to dilate under the observation of endoscope. 5) Made by high pressure resistance material, ensures the safety of dilation.