The 4PXC-D cased coil is a dedicated downflow model, which can also be configured for horizontal right with an optional kit. The 4PXC-U is a upflow/downflow model, which can be adapted to horizontal left/right with an optional kit. Both are 1.5–5 ton units. Our all-aluminum coils are designed to work with your outdoor condensing unit or furnace. They are matched in size, efficiency and capacity to ensure optimal performance of your home comfort system. The coil serves as a heat exchanger—working with your heating system in the winter and your cooling system in the summer—featuring a new, enhanced fin design for greater heat transfer.