The APTW4-18100213-1620-D42-D22 from AmpliTech, Inc. is a RF Amplifier with Frequency 18.1 to 21.3 GHz, Gain 46 dB, Gain Flatness ±2 dB, Noise Figure 1.70 dB. Tags: Drop-In, Low Noise Amplifier. More details for APTW4-18100213-1620-D42-D22 can be seen below.