A sheath for passage of an implant , comprising: an elastic outer tubular layer defining an initial elastic lumen extending axially therethrough, the initial elastic lumen having an initial diameter; and an inner tubular layer having a thick wall portion integrally connected to a thin wall portion , wherein the thick wall portion has a C-shaped cross section with a first longitudinally extending end and a second longitudinally extending end and wherein the thin wall portion extends between the first and second longitudinally extending ends so as to define an expanded lumen extending axially through the inner tubular layer , the expanded lumen having an expanded diameter larger than the initial diameter of the initial elastic lumen and; wherein the inner tubular layer , in a compressed condition, extends through the initial elastic lumen of the elastic outer tubular layer with the elastic outer tubular layer urging the first longitudinally extending end under the second longitudinally extending end of the inner tubular layer ; and wherein the inner tubular layer , in a locally expanded condition, has the first and second longitudinally extending ends radially expanded apart, against the urging of the elastic outer tubular layer by passage of an implant , into a less overlapping condition with the thin wall portion extending therebetween to form the expanded lumen; and wherein the inner tubular layer is configured to be urged by the outer elastic tubular layer into the compressed condition after passage of an implant through the expanded lumen, characterized by further comprising at least one longitudinal rod coupled to an inner surface of the outer tubular layer and extending into the initial elastic lumen wherein the longitudinal rod is configured to provide a bearing surface to facilitate relative movement of the inner tubular layer within the outer tubular layer when moving between the locally expanded condition and compressed condition. an elastic outer tubular layer defining an initial elastic lumen extending axially therethrough, the initial elastic lumen having an initial diameter; and an inner tubular layer having a thick wall portion integrally connected to a thin wall portion , wherein the thick wall portion has a C-shaped cross section with a first longitudinally extending end and a second longitudinally extending end and wherein the thin wall portion extends between the first and second longitudinally extending ends so as to define an expanded lumen extending axially through the inner tubular layer , the expanded lumen having an expanded diameter larger than the initial diameter of the initial elastic lumen and; wherein the inner tubular layer , in a compressed condition, extends through the initial elastic lumen of the elastic outer tubular layer with the elastic outer tubular layer urging the first longitudinally extending end under the second longitudinally extending end of the inner tubular layer ; and wherein the inner tubular layer , in a locally expanded condition, has the first and second longitudinally extending ends radially expanded apart, against the urging of the elastic outer tubular layer by passage of an implant , into a less overlapping condition with the thin wall portion extending therebetween to form the expanded lumen; and wherein the inner tubular layer is configured to be urged by the outer elastic tubular layer into the compressed condition after passage of an implant through the expanded lumen, characterized by further comprising at least one longitudinal rod coupled to an inner surface of the outer tubular layer and extending into the initial elastic lumen wherein the longitudinal rod is configured to provide a bearing surface to facilitate relative movement of the inner tubular layer within the outer tubular layer when moving between the locally expanded condition and compressed condition. <EOS>