A device for treating a vessel comprising: a catheter; an expandable implant having a main lumen and at least one target portion (400, 402); at least two secondary sleeves (304a, 304b, 704a, 704b) each comprising a sheet of material, each wrapped circumferentially around the expandable implant forming at least two adjacent tubes; each tube having at least one tube end adjacent to another tube end; each sheet having first and second major surfaces and a plurality of openings extending from the first major surface to the second major surface; at least two coupling members (714a, 714b), one for each secondary sleeve, cooperating with the plurality of openings for releasably coupling portions of each sheet together to constrain the expandable implant in an intermediate configuration; a primary sleeve extending around the at least two secondary sleeves and the expandable implant for constraining the device to a collapsed configuration suitable for endoluminal delivery, wherein the primary sleeve is held in position by a primary coupling member; wherein in the intermediate configuration the diameter of the implant is constrained in a diameter smaller than the expanded configuration and larger than the collapsed configuration; wherein the target portion (400, 402) comprises a side branch fenestration, a fenestrable portion that is punctured to form a side branch fenestration or a drug eluting element, the or each target portion (400, 402) being oriented such that it is covered by one of the at least two secondary sleeves (304a, 304b, 704a, 704b) in the collapsed configuration and in the intermediate configuration, and the device being configured such that, upon expansion of the secondary sleeve the target portion (400, 402) is exposed to vasculature of a patient. a catheter; an expandable implant having a main lumen and at least one target portion (400, 402); at least two secondary sleeves (304a, 304b, 704a, 704b) each comprising a sheet of material, each wrapped circumferentially around the expandable implant forming at least two adjacent tubes; each tube having at least one tube end adjacent to another tube end; each sheet having first and second major surfaces and a plurality of openings extending from the first major surface to the second major surface; at least two coupling members (714a, 714b), one for each secondary sleeve, cooperating with the plurality of openings for releasably coupling portions of each sheet together to constrain the expandable implant in an intermediate configuration; a primary sleeve extending around the at least two secondary sleeves and the expandable implant for constraining the device to a collapsed configuration suitable for endoluminal delivery, wherein the primary sleeve is held in position by a primary coupling member; wherein in the intermediate configuration the diameter of the implant is constrained in a diameter smaller than the expanded configuration and larger than the collapsed configuration; wherein the target portion (400, 402) comprises a side branch fenestration, a fenestrable portion that is punctured to form a side branch fenestration or a drug eluting element, the or each target portion (400, 402) being oriented such that it is covered by one of the at least two secondary sleeves (304a, 304b, 704a, 704b) in the collapsed configuration and in the intermediate configuration, and the device being configured such that, upon expansion of the secondary sleeve the target portion (400, 402) is exposed to vasculature of a patient.