The 4953-3Z from ARRA Inc. is a RF Variable Attenuator with Frequency 3.7 to 4.2 GHz, Attenuation Range 3 dB, Attenuation Accuracy ±0.3 dB, Power 5 W, Insertion Loss 0.3 dB. Tags: Module with Connectors, Rotary, Continuously Variable. More details for 4953-3Z can be seen below.