Retrievable vena cava filters for the temporary or permanent prevention of Pulmonary embolism (PE) are disclosed. A filter in accordance with the present invention has a tube-within-tube structure with overlapping semi-spheres. The semi-spheres comprise a plurality of expandable legs. The first tube may have a first set of expandable legs and a plurality of slots allowing for deployment of a second or third set of expandable legs on the second tube. The filter of the present invention may be retrieved by a catheter and snare. The third set of expandable legs conveys the vector force from the closing of the first set to the second set to cause it to collapse.
