＜現象＞
「赤いカード箱」をなでると「青いカード箱」に変化します。
観客に箱を手渡しますが，異常はなく「レギュラーデック」が入っています（＝お好きなマジックに続けられます）。
＜特長＞
「シェル系ギミックの発展型」で，レギュラーデック自体の改造不要です。
事後処理は一瞬で終わり，箱ごと渡せます（＝レギュラー状態）。
※動画中でも「即手渡し」するように見えるほどです。
強耐久性
塩ビ系の素材なので，壊れたりヨレたりしません。
→紙工作では作れない専用品です。
ゴム・スレッド不要
フラップカードのような「デリケート部品（ゴム板，伸縮糸）」は不要です。
→メンテナンスの苦労がありません。
「演技冒頭（オープニング）」「途中演目」どちらにも使えることを意図したアイディアで，「カードマジックの演出と組み合わせる」のも面白そうです。
参考（英原文）
C4 is the ultimate color changing card case, in which a case of playing cards changes from red to blue. It is the culmination of years of thought, trial and error, and a goal. The goal was to visibly change the color of a playing card case. But it wasn't just to do that. It was to create a magical moment that was so clean and so fair that Jonathan Levit would want it as part of his act. And now it is.
C4 can be performed when the magician is ready. It doesn't have to be done as soon as the playing cards are introduced. It's so visual that it seems like real magic.
"C4 was created so that I could use it in my act. And I do. Every time. And it kills. Every time.
"It wasn't until it was tried and tested, a lot, that I started the process of producing this for others to use. It took nearly two years to perfect." The gimmick is precision made. It comes beautifully packaged and complete with everything you need to start performing it right out of the box!"
- Jonathan Levit
"How good is C4? I plan on putting it into my own show, Immediately! Elegant and visual and the perfect mistress to your color changing deck routine. Love it!"
- Steve Valentine
"C4 is like carrying a camera trick in your pocket. It is stunning visual magic. The handling could not be more clear. C4 yourself what real magic looks like."
- Mike Caveney
"This is quality magic, beautifully packaged, that will deliver dividends..."
- David Regal/Genii Magazine
"I'll admit it. When I saw it in his performance, I didn't see it coming. I didn't think Jonathan could really do it. I was fooled. But now I know why! C4 is a beautiful gimmick to accomplish an offhanded miracle. Exactly the way real magic should look!"
- Jim Steinmeyer
"Dang! That looks great."
- Richard Kaufman
"Jonathan Levit's color changing card case is a stunning, powerful piece of magic that any serious card worker will appreciate. It's so well thought out that even the novice performer will stun people with it."
- Bruce Gold
"Jonathan Levit's C4 is a brilliantly thought out and extremely clever gimmick. The thinking behind it is pure genius. Jonathan thought of everything for every situation and every angle. It will leave your audience with the feeling they just witnessed real magic."
- Suzanne
"I can't imagine any serious card magician, amateur or pro, not having this."
- Karl Johnson
"Kudos to Jonathan Levit for creating this excellent effect."
- Peter Pitchford/Magic Magazine
"It's killer."
- Wayne Kawamoto, Magic.About.com