Ther X-rings are better than O-rings when used in a dynamic application. The standard specifications of X-rings are the same as AS568 O-rings. Characteristics of X-rings are as follows : 1. The “X” profile creates a stable seal that is more resistant to rolling in the groove than an O-Ring. It will be helpful to extend the period of use. 2. Multi-lobed design provides more sealing surfaces than standard O-Rings. 3. Lower breakaway force and reduced operating pressures make them ideal in reciprocating applications.