An endoluminal prosthesis introducer including: a rotatable inner cannula (250, 350) including a proximal end; a proximal tip (240, 340) disposed at the proximal end of the inner cannula (250, 350) and including a distal end; and a retaining member including an engaging member (270, 270A, 270' 380) extending radially outward, the retaining member being disposed about the proximal end of the inner cannula (250, 350), such that rotation of the inner cannula (250, 350) with respect to the retaining member causes longitudinal relative movement of the proximal tip (240, 340) and the engaging member (270, 270A, 270' 380) between a retaining configuration and a releasing configuration wherein the proximal tip and the engaging member are spaced from one another by a greater longitudinal distance in the releasing configuration than in the retaining configuration; wherein the retaining member includes a sleeve (262, 360) disposed about the inner cannula (250, 350), the engaging member extends radially from the sleeve (262, 360), and the sleeve (262, 360) is engageable with the proximal tip (240, 340); wherein the sleeve (262, 360) of the retaining member includes an attachment mechanism (268, 368) positioned proximal of the engaging member (270, 270A, 270' 380), the distal end of the proximal tip (240, 340) includes a coupling member (256, 356) including an attachment mechanism, and the attachment mechanism of the sleeve (262, 360) is engageable with the attachment mechanism of the coupling member (256, 356) to couple the retaining member to the proximal tip (240, 340); wherein the attachment mechanism (268, 368) of the sleeve (262, 360) and the attachment mechanism of the coupling member (256, 356) are threaded; wherein the introducer includes a space radially between the engaging member and the sleeve to receive a part of a prosthesis such that the engaging member is operable to prevent a portion of the prosthesis expanding to a fully expanded configuration. a rotatable inner cannula (250, 350) including a proximal end; a proximal tip (240, 340) disposed at the proximal end of the inner cannula (250, 350) and including a distal end; and a retaining member including an engaging member (270, 270A, 270' 380) extending radially outward, the retaining member being disposed about the proximal end of the inner cannula (250, 350), such that rotation of the inner cannula (250, 350) with respect to the retaining member causes longitudinal relative movement of the proximal tip (240, 340) and the engaging member (270, 270A, 270' 380) between a retaining configuration and a releasing configuration wherein the proximal tip and the engaging member are spaced from one another by a greater longitudinal distance in the releasing configuration than in the retaining configuration; wherein the retaining member includes a sleeve (262, 360) disposed about the inner cannula (250, 350), the engaging member extends radially from the sleeve (262, 360), and the sleeve (262, 360) is engageable with the proximal tip (240, 340); wherein the sleeve (262, 360) of the retaining member includes an attachment mechanism (268, 368) positioned proximal of the engaging member (270, 270A, 270' 380), the distal end of the proximal tip (240, 340) includes a coupling member (256, 356) including an attachment mechanism, and the attachment mechanism of the sleeve (262, 360) is engageable with the attachment mechanism of the coupling member (256, 356) to couple the retaining member to the proximal tip (240, 340); wherein the attachment mechanism (268, 368) of the sleeve (262, 360) and the attachment mechanism of the coupling member (256, 356) are threaded; wherein the introducer includes a space radially between the engaging member and the sleeve to receive a part of a prosthesis such that the engaging member is operable to prevent a portion of the prosthesis expanding to a fully expanded configuration.