This is an early diaphragm shutter, the blades open to a varying degree and so act as the iris.

Coe lists three variants: Model of 1888 with horizontal delay cylinder; Model of 1889 with delay and release cylinders set at an angle on the face of the shutter; Model of 1890 with vertical cylinders and self-capping operation.

The shutter is found on many American cameras of the period. Several sizes were made: ¾" throat for 5" x 4"; 1 ⅛" for half-plate; 1 7/16" for whole plate; 1 ¾" for 10" x 8". The case was made of aluminium or brass.

This is a combined shutter and iris. The earlier version had the speed setting at 6 o'clock and the aperture setting at 7 o'clock. The improved model of 1902 had the speed dial at 2 o'clock.

Combined shutter and iris diaphragm units were usually aimed at the upper end of the market. This model though was in the cheaper range. Only one linkage rod is required between the two sets of leaves.