The HE391B from Sainty-Tech Communications Limited is a RF Amplifier with Frequency 20 to 500 MHz, Gain 15 to 16 dB, Gain Flatness ±0.5 dB, Noise Figure 3.8 dB, Output Power 19 to 19.5 dBm. Tags: Power Amplifier. More details for HE391B can be seen below.