The C 5:4X is one of four C…X models in the C Series, each uniquely suited for a range of installed applications with relatively lower power output requirements. C…X models share most features of the original (higher power) C Series models, and they share the same compact, lightweight 2U chassis. However, the C…X models are offered in both four- and eight-channel versions, offering even greater channel density and installation flexibility. Also, because the unique benefits of Class TD * are more applicable at higher power levels, the C…X models employ a cost-efficient proprietary Class D output design. Other features unique to C…X models include a universal power supply, selectable 35 Hz high-pass filter, and built-in GPIO control facilities.