.    Foldable Silicone Piano (49 Keys) Features: 1) Portable piano, 49keys,can be roll together 2) Can be played instantly, anywhere 3) the raw material is Silicon, safe and waterproof 4) Record / play keys 5) Vibrato function 6) LED screen digital display 7) Earphone function 8) Number of black key: 20; number of white key: 29 9) Power supply: 3# AA batteries / AC adapter 10) External speaker, outer 11) Size of piano:    a) Rolled: 15 x 19 x 17cm    b) Unrolled: 80 x 18cm 12) Input:100v-240V, output voltage: 6V 500-1000ma