The 50R-388 from JFW Industries is a RF Variable Attenuator with Frequency DC to 2.7 GHz, Attenuation Range 30 dB, Attenuation Step 3 dB, Power 2 W, Insertion Loss 0.35 to 0.75 dB. Tags: Module with Connectors, Rotary. More details for 50R-388 can be seen below.