A medical device may include a distal end having an expandable grasping portion with a plurality of movable branch members, and at least one filament connected to and slidably movable within at least a portion of the plurality of movable branch members. The proximal end of the device may include a handle having an actuation guide and an actuation selector connected to and movable along the actuation guide. The actuation selector may be coupled to ends of the at least one filament and may be configured to exert a force on the filament to vary the size of the grasping portion between a plurality of pre-selected discrete configurations of the grasping portion. In addition, the medical device may include a sheath member extending from the distal end toward the proximal end. The proximal ends of the plurality of movable branch members may be disposed within the sheath member.