A clip for restricting the axial movement of at least one of an inner shaft or an outer shaft relative to the other shaft, comprising: a first free end (44 1) and a second free end (44 2); an opening between the first free end (44 1) and the second free end (44 2), and defining an open end of the clip; a closed end opposite the open end; at least three control zones (66 1, 66 2, 66 3) and a plurality of intermediate zones (68 1, 68 2, 68 3, 68 4) each having a varying width (w), and each being disposed adjacent to at least one of the at least three control zones (66 1, 66 2, 66 3); characterized in that the opening at the open end of the clip has a width that increases as it extends radially inward, and that a first control zone (66 1) is located in the closed end of the clip, a second control zone (66 2) is located between the first control zone (66 1) and the first free end (44 1), and a third control zone (66 3) is located between the first control zone (66 1) and the second free end (44 2); and that a first intermediate zone (68 1) is disposed between the first and second control zones (66 1, 66 2), and as it extends between the first and second control zones (66 1, 66 2), the width (w) thereof increases and then decreases; and that a second intermediate zone (68 2) is disposed between the first and third control zones (66 1, 66 3), and as it extends between the first and third control zones (66 1, 66 3), the width (w) thereof increases and then decreases, wherein the first and second intermediate zones (68 1, 68 2) are mirror images of each other, and wherein the first and second intermediate zones (68 1, 68 2) each progressively increase in width as extending from the first control zone (66 1) to a predetermined point between the first control zone (66 1) and the second or third control zone (66 2, 66 3), respectively, and wherein the first and second intermediate zones (68 1, 68 2) then progressively decreases in width as extending further from that predetermined point to the second or third control zone (66 2, 66 3), respectively. a first free end (44 1) and a second free end (44 2); an opening between the first free end (44 1) and the second free end (44 2), and defining an open end of the clip; a closed end opposite the open end; at least three control zones (66 1, 66 2, 66 3) and a plurality of intermediate zones (68 1, 68 2, 68 3, 68 4) each having a varying width (w), and each being disposed adjacent to at least one of the at least three control zones (66 1, 66 2, 66 3); characterized in that the opening at the open end of the clip has a width that increases as it extends radially inward, and that a first control zone (66 1) is located in the closed end of the clip, a second control zone (66 2) is located between the first control zone (66 1) and the first free end (44 1), and a third control zone (66 3) is located between the first control zone (66 1) and the second free end (44 2); and that a first intermediate zone (68 1) is disposed between the first and second control zones (66 1, 66 2), and as it extends between the first and second control zones (66 1, 66 2), the width (w) thereof increases and then decreases; and that a second intermediate zone (68 2) is disposed between the first and third control zones (66 1, 66 3), and as it extends between the first and third control zones (66 1, 66 3), the width (w) thereof increases and then decreases, wherein the first and second intermediate zones (68 1, 68 2) are mirror images of each other, and wherein the first and second intermediate zones (68 1, 68 2) each progressively increase in width as extending from the first control zone (66 1) to a predetermined point between the first control zone (66 1) and the second or third control zone (66 2, 66 3), respectively, and wherein the first and second intermediate zones (68 1, 68 2) then progressively decreases in width as extending further from that predetermined point to the second or third control zone (66 2, 66 3), respectively.