A seal for a pipe coupling can include an outer gasket defining a radially inner surface defining a plurality of grooves; and an inner gasket separably joined to the outer gasket and defining a radially outer surface, the radially outer surface defining a plurality of ridges extending radially outward and including: a first ridge, each of first and second side surfaces of the first ridge angled in cross-section with respect to a radial direction of the inner gasket towards a first axial end of the inner gasket when in an uncompressed state; and a second ridge, each of first and second side surfaces of the second ridge angled in cross-section with respect to the radial direction towards a second axial end of the inner gasket when in the uncompressed state; wherein the radially outer surfaces of the inner and outer gaskets contact each other.