Adopting oil-free piston pump.
  Clean-without pollution of oil and smoke.
  Convenient-no need add oil to maintain daily.
  Safe-no plus pressure during using.
  No flow backwards pressure when the machine stops, so the liquid won't flow backwards.
  Complete plastic panels, hand-switch and foot-switch for operating easily.

Select negative pressure at will with no level for pressure adjustment, and overflow protection mechanism, safe and reliable.