Terminology

The terms "cylinder", "piston" and "rod" will always be used in this brochure in relation to the arrangement and function of the seals, namely:
The term "cylinder" indicates a component of hydraulic and pneumatic installation and may be classified in four basic types as shown in figure 1 through 4.

The static seal on the external diameter while the relative motion of the metal surface occurs on the internal diameter.

Piston Seal

The Static seal on the internal diameter while the relative motion of the metal surface occurs on the external diameter.