Adapter for . 

The X100 Holder was designed from the ground up to eliminate vignetting down to 16mm on a full-frame sensor. And with its innovative snap-lock mechanism it makes attaching and detaching the holder fast and secure.

INNOVATIVE SNAP-LOCK: The X100 Holder for easy one-handed operation with a unique and oversized CNC machined Snap-Lock knob.

Press the filter holder against the adapter ring and it immediately locks into place with a snap! Focus on the shot and not the holder every time you detach/reattach to the adapter ring.