A catheter device having a shaft that extends from a proximal end to a distalend to carry on its distal end a self-expanding implant for intraluminaladvance on a guidewire and delivery of the implant to an implant site byproximal withdrawal of a sheath that lies radially outside the implant in thecatheter, the catheter including a first shaft element to pull the sheathproximally and a second shaft element to push the implant distally to preventthe implant moving proximally with the sheath when the sheath is pulledproximally, wherein the second shaft element carries a stopper for abuttingthe implant, the stopper comprising proximal and distal portions havingdifferent radiopacities.
