Various wall anchors exist for hollow walls, including self-installable anchors and expandable anchors.  Some of these anchors define outer threads adapted to engage the friable material that constitutes part of the wall structure, such as in U.S. Pat.  No.  5,833,415 issued on Nov. 10, 1998 to McSherry.  Other such anchors include a toggle member that is adapted to pivot between a longitudinal insertion position and a transversal retention position, wherein the toggle member adopts its transversal position once behind the wall, so as to then be drawn towards the wall until it engages a rear hidden surface of the hollow wall, thereby firmly securing the anchor to the hollow wall, such as in U.S. Pat.  No.  6,250,865 issued on Jun. 26, 2001 to McSherry. 
Anchoring devices encounter various wall mediums, such as hollow walls and solid walls, and in the case of the former, the thickness of the hollow wall may vary.  Anchoring devices thus need to have constructions suitable for such mediums. 
The present invention seeks to meet these needs and other needs.