A winged insert holds a magnet and includes a flat base having two sides with wings that have U-shape or V-shape. Each side's wing extends off the side of the base in a first direction and then curves back at an outward-facing angle. The wings act similar to barbs or arrow heads to allow the insert to be inserted into a slot on a trim or decking board while preventing the insert from being removed from the slot after insertion. The winged insert may include alignment holes or pins for positioning a removable spacer adjacent the winged insert. The spacer may include a tray or other sidewalls on an opposite side for holding a magnetic conductor. For trim applications, the conductor may be affixed to a wall during an installation process before removing the spacer. For flooring applications, the conductor may be a top metal surface of a joist clip.