The Quad Ring thanks to its unique design provides a superior seal compared to regular O-Rings. This increases your chances of a seal on difficult to seat posts and even some dip tubes with bent flanges.
The quad design covers a larger surface area as the material compresses against the flange of your liquid and gas dip tubes. These o-rings can provide up to three times the surface area in contact. A better o-ring for a better seal. Ball or pin lock kegs.