Balloon inflation device 1) High precision modeling make sure the barrel body/cavity exactly conformity from bottom to top . 2) seal-ring to seal pressure, that avoid pressure decay when inflation. Single seal-ring can avoid re-contamination. 3) Non O-ring stop-cock design can avoid re-contaminiation. Unique relief slot design allow successfully processeven at extremely high pressure 4) Pressure gauge fix to the syringe by latch ensure successfully process 5) High precision gauge ensure pressure increase stably while inflate. And can return to 0 exactly while release pressure. Which pass Japanese Clincal test 6) Ergonomic design , suitable for right and left hand. Quick-release design, allow deflation within 0.1 second