The CSK-20-4G SQ from Crane Aerospace & Electronics is a Directional Coupler with Frequency 2600 to 5200 MHz, Coupling 20 dB, Coupling Variation ±1 dB, Frequency Sensitivity ±0.75 dB, Directivity 19 dB. Tags: Module with Connectors. More details for CSK-20-4G SQ can be seen below.