Ingersoll Rand fluid products, air tools, and compressors. If your choice is a Diaphragm or Piston Pump from Ingersoll-Rand / ARO, then the choice is a solid one. Why? Because an air-operated pump, while it can be judged and measured from several criteria, none is more critical than the design and operational integrity of the air motor; and ARO know air motor technology. They have the patents to prove it, including the sole ownership of the industries first "unbalanced" air valve. This design along with some more recent innovations, have kept ARO the benchmark throughout the air-driven pump industry. Simple in its concept, sensational in performance, the "unbalanced" design is the best most efficient path to trouble-free fluid handling you're going to find.