... of silicone,easy to carry,waterproof, foldable,anytime and anywhere you can play it. Standard 61 Simulation Keys,Sustain function, Vibration ... Fill-in, 16-stage volume adjustable,32-stage tempo speed, You can plug in headphones into the headphone jack and listen ... Keyboards for Learning the Piano. Are you an experienced keyboardist looking for something to use as you travel around the country. Or, are ...