The discs are made of cardboard (not plastic as I read on another review). It's not a big deal but I wanted to clarify that. I put 4/5 just to attract readers to this fact. Ideally, two discs including ports 4.90 seems a reasonable price (even if it had to listen to manufacture 0.20).
I appreciate the fact that they are sold in pairs, it allowed me to provide my parents (it's nice when you have two cars ...).