A cover (214, 216) for covering food comprising: a base: and a flexible wall (217, 218) extending upwardly from and surrounding said base to define a chamber with an opening, said flexible wall (217, 218, 238) having an initial state where the opening is a first size and having a final state where the opening is a second size different from said first size; wherein the flexible wall (217, 218, 238) includes a first section that extends upwardly from and surrounds the base, the first section having a bottom portion attached to the base, and a top edge spaced from the bottom portion; characterised in that the flexible wall (217, 218) also comprising a second section (218, 238) that extends radially inwardly from the top edge of the first section; wherein the cover has a maximum opening state (d max) that may be greater than the initial opening state (d 0) whereby upon inserting food of a certain size ranging from the maximum opening(d max) to initial opening (d 0) within said chamber, said second section of said flexible wall (217, 218, 238) compresses, moves or curls downward creating a seal (So) between the food and the cover (214, 216); wherein said base further includes a first section having a first thickness (t 1) and a second section having a second thickness (t 2) less than said first thickness (t 1), said second section being located at approximately a center of said first section; and wherein said base further includes a third section, between the first and second sections having a third thickness (t 3), wherein the third section has a third thickness less than said second thickness (t 2) and comprises a hinge portion (226, 228), and wherein the hinge portion (226, 228) is configured to allow the second section to transition between a convex state and a concave state. a base: and a flexible wall (217, 218) extending upwardly from and surrounding said base to define a chamber with an opening, said flexible wall (217, 218, 238) having an initial state where the opening is a first size and having a final state where the opening is a second size different from said first size; wherein the flexible wall (217, 218, 238) includes a first section that extends upwardly from and surrounds the base, the first section having a bottom portion attached to the base, and a top edge spaced from the bottom portion; characterised in that the flexible wall (217, 218) also comprising a second section (218, 238) that extends radially inwardly from the top edge of the first section; wherein the cover has a maximum opening state (d max) that may be greater than the initial opening state (d 0) whereby upon inserting food of a certain size ranging from the maximum opening(d max) to initial opening (d 0) within said chamber, said second section of said flexible wall (217, 218, 238) compresses, moves or curls downward creating a seal (So) between the food and the cover (214, 216); wherein said base further includes a first section having a first thickness (t 1) and a second section having a second thickness (t 2) less than said first thickness (t 1), said second section being located at approximately a center of said first section; and wherein said base further includes a third section, between the first and second sections having a third thickness (t 3), wherein the third section has a third thickness less than said second thickness (t 2) and comprises a hinge portion (226, 228), and wherein the hinge portion (226, 228) is configured to allow the second section to transition between a convex state and a concave state.