in a pull - out spray head faucet or hand shower an insert is disposed in the tube spout to keep the pull - out spray head or wand from wobbling when it is seated in the tube spout . the insert is generally tubular and is shaped and sized to fit into the tube spout . the insert has two opposed tabs on the interior walls which engage two wings on an adapter which is mounted in the wand , thereby securing the adapter and wand against wobble .