The 4228-63.75 from Weinschel by Spectrum Control is a RF Variable Attenuator with Frequency 800 MHz to 3 GHz, Attenuation Range 63.75 dB, Attenuation Step 0.25 dB, Power 180 W, Insertion Loss 6 dB. Tags: Benchtop, Programmable, Digital, USB Controlled, Computer Controlled. More details for 4228-63.75 can be seen below.