The 5800BL15B100 from Johanson Technology is a Balun with Frequency 5.725 to 5.875 GHz, Amplitude Balance 0.75 dB, Phase Balance 8 Degree, Insertion Loss 1.0 dB, Power 3 W. Tags: Ceramic, Surface Mount, Unbalanced to Balanced. More details for 5800BL15B100 can be seen below.