This speaker includes built-in low-voltage protection, which automatically cuts off the circuit if the battery voltage drops below 15v to prevent damage or safety issues. It offers an extended range of up to 52 feet and improved connectivity, delivering clear high notes, deep bass, and true HD sound through its 20W built-in speaker. The price drops from $24.99 to $19.99. Shipping is free for prime members or on orders over $35.