http://iscoresports.com/

What do the gray lines indicate on the hit charts? The user guide only refernces red/green/yellow

Red = Out
Green = Hit
Yellow = reached base by some other means (error, fielder's choice, etc)

The "gray" line is actually a shadow for popups / fly balls so you can see the direction of the ball when the lines are curved.

Documentation is available at:

http://iscoresports.com/baseball/training.php" onclick="window.open(this.href);return false;