The SMSL SA300 is loaded with features and customization. Could this be the best amplifier under $150? The amplifier itself came with a few pamphlets and a user manual. Although the user manual looks small, it was quite thorough on the operation of the amplifier and remote control. The box also contained a USB cord for the DAC, a massive power supply that is capable of outputting 162 watts, a Bluetooth antenna and a remote control.