Sterling Seal & Supply X-Rings, also known as Quad-Rings, have a double sealing function as compared to an O-ring and can be used in a wide variety of static and dynamic sealing applications The four-lobed design provides twice the sealing surface in comparison to a standard O-ring The double-seal action requires less squeeze to maintain an effective seal This reduction in squeeze means less friction and improved seal life Additionally, X-Ring parting lines are between the lobes, away from the sealing surface This eliminates the issue of leakage often resulting from a parting line's irregular surface as found on an O-Ring X-Rings are measured by their Cross Section and ID, just like O-rings The seal does not tend to roll in the groove during reciprocating movement, requires less radial squeeze than a comparable O-ring and less friction means less wear, and thus a longer service life It has very good sealing efficiency due to it special profile and a lubricant reservoir formed between the sealing lips improves start up These packing's were designed to overcome the weaknesses of O-Rings – such as high friction, spiral failures and leakage from compression set One Quad Ring (X-Profile Ring) low friction seal can replace two U-Cups in many applications