Feature:1. [Adjustment Knob] 2.1 channel BT digital amplifier board, left and right channel high and bass and subwoofer independent adjustment, 360 degrees stepless tuning.2. [HIFI Sound Quality] This BT power amplifier board supports AUX sound input, pure HIFI sound quality, treble pure and transparent, gentle and delicate midrange, bass shock.3. [APP Control] Wireless amplifier board supports for Android, for iOS system, APP visual operation playback mode, volume, sound, up and down song control, play pause, play mode.4. [High Output Power] Wireless subwoofer amplifier board supports maximum 50W (left channel), 50W (right channel) and 100W (subwoofer) channel output.5. [Safety Protection] This BT digital amplifier module has electrostatic protection, over current protection, short circuit protection, and overheating protection.Specification:Item Type: BT Amplifier BoardMaterial: PCBSound Channel: 2.1BT: 5.0Input Mode: BT, AUX, USBPower Supply: 12-24V, 5ASound Output: Left and Right Channel, Subwoofer, 3.5mm/0.1in Stereo OutputFrequency Range: 20Hz-30KHzSNR: 92dBOutput Power: 50W x 2 (Left and Right Channel) and 100W (Subwoofer)Left and Right Channel Matching Speakers: 10W- 100W, 4-8Subwoofer Adaptable Speakers: 20W-200W, 4-8Protection Mechanism: Electrostatic Protection, Over Current Protection, Short Circuit Protection, Overheating ProtectionSpecial Features: Support for YS Audio APP Control.Package List:1 x BT Amplifier Board2 x Cover Plate6 x Knob Cover1 x Heat Sink1 x Sponge Sheet1 x Screwdriver8 x Golden Screw Post 9 x Black Screws