New Way standard air bushings enable frictionless air cylinders. The O-rings in conventional hydraulic and pneumatic cylinders create significant friction. In measurements and test loading, that friction can be an issue. Instead of O-rings, the seal for the air bearings is the high-pressure air film generated by the bearing. So, with a 60 psi input pressure to the bearing you could expect to generate 30 psi in the air film. This pressure is usually used for bearing functionality, but it also doubles as a seal as nothing of a lower pressure will try to get into the gap, it would be like water running uphill.
As a result, air bushings create frictionless air cylinders without hysteresis and can be used to apply loads on spinning objects while measuring the torque generated.
New Way Air Bearings