Want to buy sayodevice

Ok, so I have some questions about buying a sayodevice. 1. Is there different types of sayodevices and if yes, what are the differences between them? 2. I'm getting one to play Geometry Dash, what should I look for? 3. Where should I order it? I'm from Colombia, South America. 4. Any important info I should know about sayodevices? 5. Finally, I don't know about switches or things like that if someone could explain