The 2100BL15A100 from Johanson Technology is a Balun with Frequency 2.1 to 2.2 GHz, Amplitude Balance 2.0 dB, Phase Balance 10 Degree, Insertion Loss 1.0 dB, Power 3 W. Tags: Ceramic, Surface Mount, Unbalanced to Balanced. More details for 2100BL15A100 can be seen below.