(1) Since this pump is a water ring type, there are no problems if the intake air contains steam or water droplets.(2) Good durability with both-end support bearings.(3) Easy operation and maintenance are possible because there are no mechanical contact parts other than the bearings and gland.(4) Low-noise pump thanks to its silence design.(5) For low and high vacuum pressure types, a fixed port type and check ball type are used respectively so that the shaft power becomes smaller within the operating range.