The 5500BL15U0100 from Johanson Technology is a Balun with Frequency 3 to 8 GHz, Amplitude Balance 2.0 dB, Phase Balance 20 Degree, Insertion Loss 1.8 dB, Return Loss 9.5 dB. Tags: Ceramic, Surface Mount, Unbalanced to Balanced. More details for 5500BL15U0100 can be seen below.