Casio CTK 3500 Tutorial: Answers to Commonly Asked Questions
Casio CTK3500 Review 2021: The "Touchy" Brother of CTK2550
Is the Casio CTK-3500 decent for recording? I noticed that it doesn't have the MIDI functionality, but is that really a big issue? - Quora
Does The Ctk 3500 Record Music? – HighVolMusic
CTK-3500 | CASIO Music
Amazon.com: Electric Keyboard 61 Key Piano Children's Musical Instrument Toy Microphone Recording Multi-Function Kids Piano Keyboard Portable (Batteries not include) : Musical Instruments