The DC 10-BQB-(***-***)-B-(**) from The Waveguide Solution is a Waveguide Coupler with Frequency 2.6 to 3.95 GHz, Coupling 10 dB, 20 dB, 30 dB, 40 dB, Directivity 25 dB. Tags: Broadwall Coupler. More details for DC 10-BQB-(***-***)-B-(**) can be seen below.