The MagSafe® Ring is used to make any phone case MagSafe® compatible. 

MagSafe® makes it possible to easily take LoveHandle for MagSafe® products off of your case in order to expose the wireless charging capabilities on the back of your phone. We recommend using a hard plastic case to ensure the MagSafe ring sticks securely. 

Cases made from silicone, glass, or textures, such as leather, will not stick well with the MagSafe ring. 

Check your case to make sure that it doesn't already have MagSafe magnets built into it.  If it does, you do not need the MagSafe converter.