The BD4859N50100A00 from Anaren Inc is a Balun with Frequency 4.8 to 5.9 GHz, Amplitude Balance ± 1.5 dB, Phase Balance 8 Degree, Insertion Loss 0.6 dB, Power 1 W. Tags: Surface Mount, Unbalanced to Balanced. More details for BD4859N50100A00 can be seen below.