Sugu ni mantan! Power Meter!!

The Cyan Switch is a Japan-exclusive (until the Wii U Virtual Console) e-Reader card for use with Super Mario Advance 4: Super Mario Bros. 3. It was released in Series 2 in Japan.

Once scanned, the Power Meter is halved, making it much easier to run and fly throughout stages. This opens up many new areas the player can use to fly across the stage.

Japanese
すぐにまんたん! パワーメーター!!

Translation
Maintain right away! Power Meter!!