RPB-XL is our extra-large portable speaker. It is small enough to be a portable speaker that you can take anywhere but big enough where our engineers were able to pack punchy bass and great volume into a rugged boombox design.SoundThe RPB-XL has incredible sound quality. It has an 18-Watt RMS amplifier dedicated to the low frequency and it has an additional 6 x 2 watts RMS to play the highs. It goes incredibly loud and the passive radiators really deliver low frequencies normally not available on a portable speaker.Dual USB’sWe have one USB dedicated for playing back your tracks and another dedicated to charge your phone or other portable device.Big Battery!The RPBXL uses a 7.4v/4000mAh Lithium-ion battery which supports up to 32 hours playback at 20% volume, 16 hours of playback at 40% volume, and 5 hours of Playback at max volume. We also added 5 LED’s that tell you how much battery life you have left. We made sure to add this because it’s a buzzkill when you want to party and unexpectedly have less battery life then you had thought.TWS – True Wireless StereoThe TWS function allows you to wirelessly connect 2 of these speakers together to give you stereo sound. This will give you a left and right channel which translates into true stereo surround sound. If you want amazing sound in your bedroom you can put one of these on each side of your room and it will sound like you have a full surround sound speaker system!