This is a small iris barrel lens clamp mounted on a 4X4 inch Graflex "C" board. Very useful for clamping small barrel lenses. Maximum opening is 1 13/16 inch and minimum is 1/4 inch. Very useful for mounting those small barrel lenses - iris clamp could of course be mounted on any other lens boards with suitable screws. $90 OBO plus shipping of $12 to Continental USA and Canada. Paypal only.