The 67 Designs' MagMount G3 comes with four (4) metal plates that can be attached to the outside or the inside phone cases.
Placing the Small Metal Strips.
The two small metal strips are for use with phones Apple MagSafe or Qi chargers. The user has to install these specifically shaped metal (non-metalic) strips north and south around the coil as shown here.
Finding the coil area in Apple cases is normally simple as Apple indicates the circle of the MagSafe area in most cases. Some 3rd party cases may not indicate the location. If that is true for your case, place the MagSafe charger on the case to determine it's location.
Place the small curved metal strips north (top) and south (bottom) around that area as shown above. Allow about 3mm or 0.125" from the edge of the coil so the strips stay away from the coil and will align with the magnet arrays on the MagMount G3 device holder.
The above image shows how a MagSafe or MagSafe alternative snaps to the Apple MagSafe Coil outer magnets. If you installed them correctly, you will see the metal strips are outside the zone of power induction that charges the battery. (CAUTION, never place any metal inside the MagSafe induction area.)
For more information on how the MagMount G3 works with an Apple MagSafe Charger or eveb competitor Qi chargers watch this video.
If you need more metal strips, you can order a new set of plates (2 small and 1 large) here.