of the first group here the longitudinal slots of the second group may show a width from approximately 3 to 7 mm and a length from approximately 10 to 15 cm with the longitudinal slots here being limited by longitudinal webs which show a width from approximately 1 to 5 mm fig1 shows a sealing inner sleeve with a perspective view from the front the sealing inner sleeve is provided with the reference character 10 and shows a coiled metallic band 12 with its band parts overlapping at the ends in this coiled state the sealing inner sleeve 10 is held by a locking device located in the interior not discernible in fig1 the locking device is here embodied such it allows a widening with regard to the diameter of the sealing inner sleeve 10 however blocks any deformation in the opposite direction suitable locking mechanisms and locking devices are widely known for example from de 44 01 318 c2 and ep 0 805 932 b1 mentioned at the outset in the state shown the sealing inner sleeve 10 is a cylindrical body with a center axis x the sealing inner sleeve 10 shows two end sections 14 15 with an intermediate section 16 located between these here the end sections 14 15 are massive metal sections while the intermediate section 16 comprises a plurality of longitudinal slots 30 extending in the circumferential direction of the sealing inner sleeve 10 which are distanced by the longitudinal webs 40 the longitudinal slots 30 and the longitudinal.