Stealth is the groundbreaking video game integrated core trainer. Imagine having fun while you exercise, focusing on high scores instead of counting out reps. You'll have so much fun playing the game, you'll forget you're working out! Stealth carefully calibrates with your phone s motion detector to recognize every movement you make. It then translates those movements into gameplay actions on the screen of your smartphone, turning your body into a "joystick" and letting you control mobile games with core training movements. Stealth is the only Plank core trainer with 360 degree motion. The proprietary multi-directional dynamic design allows you to attack your core from every angle.