The FiiO BTR Series consists of portable Bluetooth amplifiers and receivers designed to enhance audio quality for mobile devices. These devices support various high-resolution audio codecs, allowing users to enjoy superior sound when streaming music or watching videos on smartphones and tablets. Each model in the BTR Series features a compact design, making them easy to carry and use on the go. They often include built-in microphones for hands-free calls and offer long battery life, ensuring that users can enjoy their favorite audio without interruptions.