The Combination Model "D", can play both 2 and 4 minute cylinders, and was supplied with both "C" and "H" reproducers.
This model was factory modified for use not only with standard cylinders, but with ICS Language cylinders, as well. The ICS cylinders were recorded at half the speed of music cylinders (80 vs. 160 rpm) so frequent adjustment of the speed was necessary. By the time of the model "C" Standard, the speed control had been placed under the bedplate. For this modified "D" however, it is placed back on top to facilitate frequent speed changes.
The other enhancement that the ICS modification offered was a repeater that could repeat the last few sentences (grooves) from the cylinder. The lever for this is seen to the lower right of the reproducer.