From Nikon:
Adoption of ebonite resin for an elegant look and feel that creates a unique and rich texture over time
TOKYO - Nikon Corporation is pleased to announce the release of the Soft Shutter Release AR-11, developed for use with the Nikon Df FX-format digital SLR camera.
The AR-11 is an optional accessory that may be attached to the camera by screwing it into the release socket on the camera's shutter-release button. Adoption of ebonite resin for the top surface of the AR-11 allows users to enjoy a soft and light feel when pressing the shutter-release button. Ebonite resin creates a unique and rich texture over time that melds with the finger. It is often used in high-end fountain pens and the mouthpieces of wind instruments such as saxophones and clarinets.
The combination of adoption of a material with a soft and light feel for the AR-11, and the utilization of a magnesium alloy for the elegant body and large metal mechanical dials, excellent in their ability to offer simple visual confirmation of settings, for the Df increases the superior look and feel of the camera as a precision instrument. Users can further increase their enjoyment of owning the Df with the texture and operational feel of their own camera that changes according to the way they use it.