This aluminum extension/adapter ring allows you to use the SquareHood with a UV filter.
Because of the way the X100 has been designed, you can not fit a filter directly to the lens, the glass protrudes too far when focusing on close objects, meaning it will collide with the glass of the filter and can cause serious damage to the lens. This ring shifts the filter out 4mm to avoid this collision.
This can also be purchased to fit the SquareHood Mk I to your x100 or x100s.
