The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From JINPING YI:
Check your heart heart rate with iPhone, Anywhere, Anytime, in Seconds!This app measure the heart rate by detecting the color change of blood during heart beat.Put the tip of your finger on the iPhone's back camera, and your heart rate will be shown.NOTE: Make sure that your fingertip completely and gently covers the camera lens. Pressing too hard reduces blood flow in your finger and it's harder to get a result. Make sure that your fingers are not cold.The measurement will be restarted once your finger cover the lens move. So do not move in measuring heart rate.If the iPhone does not have flash, try to use it in a good lighting environment. The kids could use the thumbnail to cover the lens since the kids' finger is too thin.