The upgraded 88-key digital piano keyboard with a portable carrying case will be a perfect musical instrument whether for beginners or intermediate users. The most important improvement is the dynamical adjustment by long-pressing transpose+ button. And comparable with the PVC panel the silicon panel will effectively avoid hidden malfunction. In addition the external sound will present louder sound than a built-in one which enhances outstanding acoustics. Teaching function helps the user to learn demos easily and Bluetooth function is convenient for the user to follow playing with music. Additional features including protection function MIC function MP3 function recording function drum kit and chord will provide better playing experience. If you are looking for an 88-key digital piano keyboard don't hesitate to buy it! --128 Rhythms 128 tones and 20 demos multiple options --Teaching function is suitable for piano learning --MIDI interface allows connecting different smart devices --Bluetooth function facilitates following playing with music --Can connect headphones to create a quiet playing environment --88 Keys with ultra-thickness and perfect pressing depth are finger-friendly --External sound ensures louder sound than a built-in one --Dynamical adjustment helps you to play a more attractive piece --Silicon panel equipped with buttons is more safe and reliable --Can be charged through power bank computer USB or power strip --Long battery life up to 12 hours after 4 hours charging --Secure material & ASTM certification guarantee reliable usage --The waterproof carrying case is convenient for storing & carrying keyboard --Can be connected to sustain pedal to meet certain needs of performance --The keyboard will automatically reset when the battery voltage below 3.5 V