Abstract: A flexible, resilient incompressible seal for a butterfly valve is disclosed formed from a loop having a perimeter mounting surface and a perimeter sealing surface with first and second oppositely disposed axial surfaces extend between the perimeter sealing and mounting surfaces. Channels are positioned in the axial surfaces in spaced relation around the seal. The channels extend from the perimeter mounting surface toward the perimeter sealing surface and provide fluid communication to the perimeter mounting surface allowing fluid trapped against the perimeter mounting surface to escape when compressed by the closing of the valve. A void space is positioned in the perimeter mounting surface in the form of grooves or dimples allowing the perimeter sealing surface to deform under compression when the seal is captured within the valve and substantially restrained from deforming.