Apparatus for delivering an occlusive implant in a hollow anatomical structure, the apparatus comprising: an elongate flexible delivery tube (34, 96, 118, 158) having a proximal end and a distal end, and defining an internal delivery tube lumen (72, 98, 124) having an inner lumen diameter; a male coupler (56, 94, 120, 160) at the distal end of the delivery tube (34, 96, 118, 158) and defining an internal male coupler lumen, the male coupler (56, 94, 120, 160) including a plurality of cantilevered flexible legs (58, 126, 163) each including a distal end, each of the legs including an internal surface that defines at least a portion of the male coupler lumen and tapers inwardly toward the distal end of each leg such that an interior diameter of the male coupler lumen decreases in the proximal-to-distal direction; and an elongate control member (70, 122, 170, 222) received within the delivery tube lumen (72, 98, 124) of the delivery tube (34, 96, 118, 158) and translatable therein proximally and distally, the control member (70, 122, 170, 222) having an outer diameter less than the inner diameter of the delivery tube lumen (72, 98, 124) and the internal male coupler lumen but greater than the interior diameter of the male coupler lumen adjacent the distal end of the legs, such that when the control member (70, 122, 170, 222) is advanced distally within the male coupler lumen the control member (70, 122, 170, 222) contacts the internal surfaces of the legs to cause them to flex outwardly, said apparatus being characterized in that the male coupler (56, 94, 120, 160) defines a constant outer diameter over its length without the control member (70, 122, 170, 222) contacting the internal surfaces of the legs to cause them to flex outwardly. an elongate flexible delivery tube (34, 96, 118, 158) having a proximal end and a distal end, and defining an internal delivery tube lumen (72, 98, 124) having an inner lumen diameter; a male coupler (56, 94, 120, 160) at the distal end of the delivery tube (34, 96, 118, 158) and defining an internal male coupler lumen, the male coupler (56, 94, 120, 160) including a plurality of cantilevered flexible legs (58, 126, 163) each including a distal end, each of the legs including an internal surface that defines at least a portion of the male coupler lumen and tapers inwardly toward the distal end of each leg such that an interior diameter of the male coupler lumen decreases in the proximal-to-distal direction; and an elongate control member (70, 122, 170, 222) received within the delivery tube lumen (72, 98, 124) of the delivery tube (34, 96, 118, 158) and translatable therein proximally and distally, the control member (70, 122, 170, 222) having an outer diameter less than the inner diameter of the delivery tube lumen (72, 98, 124) and the internal male coupler lumen but greater than the interior diameter of the male coupler lumen adjacent the distal end of the legs, such that when the control member (70, 122, 170, 222) is advanced distally within the male coupler lumen the control member (70, 122, 170, 222) contacts the internal surfaces of the legs to cause them to flex outwardly, said apparatus being characterized in that the male coupler (56, 94, 120, 160) defines a constant outer diameter over its length without the control member (70, 122, 170, 222) contacting the internal surfaces of the legs to cause them to flex outwardly.