PMI Model No.  that operates from 100 MHz to 18 GHz, offers 30 dB of attenuation in 1 dB steps with insertion loss of typically 5 dB; VSWR In/Out of 2.5:1 and Attenuation Accuracy of ±2.5 dB.   This attenuator is controlled and powered via USB 2.0.  Package size is 2.25" x 1.0" x 0.33" and has SMA female connectors.