The HEM389B from Sainty-Tech Communications Limited is a RF Amplifier with Frequency 20 to 250 MHz, Gain 29 to 30 dB, Gain Flatness ±0.5 dB, Noise Figure 3 dB, Output Power 22 to 23.5 dBm. Tags: Power Amplifier. More details for HEM389B can be seen below.