The X4C40K1-20S from TTM Technologies is a Directional Coupler with Frequency 3.3 to 5.1 GHz, Coupling 20 dB, Coupling Variation ±1 dB, Frequency Sensitivity ±0.3 to ±0.085 dB, Directivity 19 to 20 dB. Tags: Surface Mount. More details for X4C40K1-20S can be seen below.