The Four-Band Splitter/Combiner (15216-SC-4B) FlexLayer module is a completely passive four band mux/demux (wavelength sensitive) module that can be used as a splitter or coupler. This card is an add-on to the Splitters/Combiner (15216-CS-x) cards of the FlexLayer product line. The functionality of the Four-Band Splitter/Combiner card is similar to the 1: 4 Splitter/4: 1 Combiner card, but the 15216-SC-4B client ports are wavelength selective and therefore cannot be interchanged. The advantage of this card with respect to the 15216-SC-4 is its lower insertion loss.