The BL-21/NF from MCLI is a 90 Degree Hybrid Coupler with Frequency 100 MHz to 1 GHz, Insertion Loss 2.3 dB, Isolation 16 dB, Amplitude Balance ±1.8 dB, Phase Balance ±10 Degree. Tags: Module with Connectors, Octave Band. More details for BL-21/NF can be seen below.