Usually we use our own coins to perform magic - it's very rare occasion when the magician asks for borrowed coins for performing. Actually, if you use half or one-dollar coins, nobody has these coins in his pocket, because they aren't current coins used today.
So, if you are going to perform with your own coins, why not use a Perfect Shell Set? This covers all of the coin, hiding 100 per cent of the coin inside!
These coins are perfect to perform any expanded shell routine and they are undetectable.
Tango Magic quality -- you know it's the best in the world.