The invention relates to a seal (160) for sealing two opposite contact surfaces along a closed contour, comprising an elastic sealing element (210), which has two opposite sealing surfaces (240) to bear against the contact surfaces in the region of the contour, two spring elements (220, 230), each of which is associated with one of the sealing surfaces, and a supporting element (250) arranged between the spring elements, wherein each spring element comprises two limbs (260, 270), one limb pressing the sealing surface associated with the spring element against one of the contact surfaces and the other limb being supported on the supporting element.