A catheter (20) having a proximal part and a distal part comprising: a first elongated tubular body (26) having a proximal part, a distal part, a proximal end having a proximal opening, a distal end having a distal opening, and an internal passage that extends between the proximal opening and the distal opening； a second elongated tubular body (28) having a proximal part, a distal part, a proximal end having a proximal opening, a distal end having a distal opening, and an internal passage extending between the proximal opening and the opening distal, where the proximal end of the second elongated tubular body defines an inner diameter larger than an outer diameter defined by the first elongated tubular body and where the inner diameter the second elongated tubular body (28) decreases from the end proximal to the end distal of the second elongated tubular body； and an elongated member (24) joining the first and second elongated tubular body, the first elongated tubular body is disposed proximally and in tandem to the second elongated tubular body, and the first and second elongated tubular body are permanently arranged so that the first and second elongated tubular body are not adjacent to each other, further comprising a third elongated tubular body (30) having a proximal part, a distal part, a proximal end having a proximal opening, a distal end having a distal opening, and an internal passage extending between the proximal opening and the distal opening, wherein each of the first, second and third elongated tubular body (26, 28, 30) is configured to receive a medical device (22) within its steps internal, at least the proximal part of the third elongated tubular body (30) is disposed within the internal passage of the first elongated tubular body (26), the third elongated tubular body (30) is des In the internal passage of the first elongated tubular body (26), and wherein the third elongated tubular body (30) is configured to move between: a proximal position in
