Here is an antique 1866 cast sad iron GENEVA HAND FLUTER Flutter Tool made in Geneva, Illinois Patented in 1866 and marked Geneva, Illinois on the handle. The base measures 5 3/4" long x 3 5/8" wide x 1" high. With the handle in place on top of the base, the piece is 4 1/2" tall. The handle measures 4 1/8" x 3" wide.
The fluter rocker-like device is a specialized kind of "sad iron", used to press the fluted ruffles on linen cuffs and collars and other trim.
Made from cast iron, the fluter would have been heated on coals in the fireplace hearth. The collar or cuff to be ironed would be moistened and laid over the grooved base. Then the heated iron would be rocked over the cloth and the linen would be perfectly pressed with rows of narrow flutes or pleats.