If you're looking for a way to securely and safely mount your very expensive LCD projector from the ceiling than look no further than the Chief LPK1! The LPK1 provides flush mounting to the ceiling, without loss of the X-Y movement.The LPK1 mount is designed to be mounted to double 2" x 4" wood stud cross bracing between two 2" x 4" ceiling joists. It can also be mounted to a concrete ceiling with a minimum thickness of 8" and a maximum drywall covering of 5/8" using 5/16" x 2-1/2" lag bolts (not included) for Fischer UX8 concrete anchors (not included) or Toggler AF8 concrete anchors (not included); or suspended from four 3/8 in. diameter ASTM A307 or stronger threaded rods (not included) which are secured to a 1-5/8" x 1-5/8" 12ga metal framing strut channel (spanning a maximum of 4 feet--not included) by 3/8" channel nuts (not included).