Sur-Seal, Inc. Buna/NBR "x" profile, commonly called quad O-Rings can be used in a wide variety of static and dynamic sealing applications. They offer twice the sealing surface in Comparison to a standard O-Ring and require less squeeze to maintain an effective seal. This reduction in squeeze means less friction and improved seal life. Additionally, 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. There are some advantages of quad Rings VS. O-rings like they avoid twisting in the groove. The seal does not tend to roll in the groove during reciprocating movement. They offer a very good sealing efficiency due to it's special profile and a lubricant reservoir formed between the sealing Lips improves start up. Sur-Seal, Inc. Buna NBR quad O-Rings are low friction compression seals. These seals were designed to overcome the weaknesses of O-Rings – such as high friction, spiral failures and leakage from compression set. Sur-Seal, Inc. Buna NBR "x" profile, quad O-Rings are an excellent choice for any application where you want to achieve a better, high performing seal. Lower Breakaway force and reduced operating pressures make them ideal in reciprocating applications.