. . "In a presently preferred embodiment, the outer sleeve 12 is formed of a lubricious material such as PTFE, to facilitate sliding the outer sleeve 12 over the inner sleeve 11. [0029] In the embodiment illustrated in FIG. 5, the collapsed inner sleeve 11 is collapsed down onto the central working length of the non-inflated balloon 27 without compressing the non-inflated balloon and thus without decre" . .