SMSL AD18 V3.1 Digital Amplifier Bluetooth NFC TAS5342A 2x 70W + Subwoofer out / 4 Ohm - Audiophonics
S.M.S.L AD18 HiFi Audio Stereo Amplifier with Bluetooth 4.2 Supports Apt-X,USB DSP Full Digital Power Amplifier 2.1 for Speaker,Small 80Wx2 Class D Amplifier with Subwoofer Output - Walmart.com