O-rings and other toroidal seals find their way into a vast array of markets and product applications. Worldwide, there are numerous specifications and standards pertaining to Basic Rings. The information in this chapter includes the most widely used specifications and standards set to help designers and manufacturers select or begin their search or custom design of the proper seal for their application. Or you may say that those o-ring kit are special design used in conveniently organized for various excavator model.