[Support hi-res Bluetooth format]: BTR7 bluetooth amplifier supports Bluetooth 5.1, LDAC/aptX Adaptive/aptX LL/aptX HD/aptX/AAC/SBC hi-res wireless format. The FiiO R&D team had a breakthrough and was able to fit 4 channels of the THX AAA amplifiers into a compact body for a fully balanced audio design – resulting in 88% more single-ended power output and 30% more balanced power output compared to previous designs.