The 2212 plate is a quick release plate designed to ensure compatibility with the following:
Fuji:
Nikon:
Not all F mount lenses have lens collars with a foot. This plate will allow you to clamp directly onto the adaptor, keeping the stress of the weight of the lens off of your camera body.
Acratech quick release plates are compatible with all Arca Swiss type clamps. The camera specific lip prevents rotation on your camera body.