The Range Shifter and Lateral Spreading Device Settings Attributes are used to either specify the presence of the device or to set machine-specific values related to these devices. For example, some machines use devices of variable thickness such as opposing sliding wedges, water column or similar mechanisms and may specify the Range Shifter setting as the desired Water-Equivalent Thickness (in mm) or as the position of the device mechanism. Such encoding is generally defined as ANALOG where the value selects the applied thickness of a device. Other machines may contain a series of interchangeable plates, whose position in or out of the beam is specified by a series of ones and zeros (i.e., 100010 would specify that plates #1 and #5 are in the beam). Such encoding could be defined as BINARY where the value selects the insertion of each plate.