You may start the conversation like the following:
B:What's it made of?
A:Metal, mainly.
B:How big is it?
A:It' not big. You can put it in your pocket.
B:What's the shape?
A:It's round and flat.
B:Who's it designed for?
A:Anyone who likes listening to music.
B:Is it a CD?
A:Right. Now it's my turn.