Zk-Tb21 2.1 Channel Bluetooth 5.0 Amplifier Board 200W Hifi Subwoofer Audio Amp Product Features Subwoofer Audio Amplifier Board: 100W+100W Bluetooth 5.0 wireless connection, Bluetooth+AUX audio input, 2.1 channel stereo output, just a little sound distortion. Note: When using AUX mode, please confirm that the Bluetooth connection of this module has been disconnected; Treble and Bass Adjustment: This digital Amp board with independent treble and bass adjustment buttons,you can directly adjust the treble and bass through the module, without using the player or speaker; Perfect Sound Quality Experience: The audio power subwoofer amplifier module with powerful chip, AM interference suppression function, shielding power inductance, low noise front stage operational amplifier, let you enjoy a more perfect sound quality experience; With Protective Function: This Bluetooth Amp module is designed with over-voltage protection, under-voltage protection, over-heat protection, short-circuit protection, with case to protective it; Easy Installation and Use: The illustration of each interface is printed on the protective plate, making it easy to install and use even without instructions. Small size: 4.4 in*2.75 in*0.78 in, easy to carry; Shipping: Shipping is complimentary within the lower 48 US States. We Do Not Ship to PO/APO Boxes, HI or Alaska We Do Not Ship Outside of the Continental US All items ship within 24-72 hours of Payment For large items that require Freight shipping a valid phone number is required to call and schedule your delivery Terms of Sale and Feedback: Feedback is extremely important to us and If you are satisfied with our transaction, please take a moment to leave Positive Feedback. YOUR Satisfaction is our #1 Priority! If there are any issues, PLEASE contact us BEFORE leaving a neutral or negative rating so that we may resolve any concerns. We PROMISE we can make you happy if you give us a fair chance. Returns / Concerns: All items qualify for returns within 14 - 30 days of receipt. Buyer is responsible for return shipping on any item that is not damaged Please be sure this is an item you want before making your purchase. Customer Satisfaction is our TOP priority! All items are IN STOCK at time of listing. Inventory changes constantly and it is impossible to maintain a perfectly accurate count of all items. Please do not penalize us if we have to issue you a refund! Thank You For Your Business!