The U-Cup (U-Packing or U-Ring) is the most compact and versatile of the many lip type seals available. In its several configurations, it may be utilized as an ID - Rod Seal, or an OD - Piston Seal.The U-cup with long thin lips has very low dynamic friction and can accommodate out-of-round or eccentric components. Other configurations with short heavy lips provide a more reliable seal at low pressures and are better suited for sealing at high pressures. These variations in design, coupled with the broad range of available Parker materials results in a very versatile line of sealing devices. Darcoid works with Parker which produces a full line of U-Cups ranging from standard AN geometry to the BT U-Cup profile, a third generation product with superior qualities.