Features & details 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. Get a strong core and a healthy back in under 3 minutes a day! The Stealth Fitness app is FREE and includes 4 games: "Speed Gliding," "Color Chase," "Galaxy Adventure," and "Space Escape." PLUS: Track your daily progress PLUS a real-time Worldwide Leaderboard. Create and compete in challenges with friends and family. No Subscription Required. Premium Game version is also available with more games! Fits any size smartphone for a fun engaging workout. Stealth takes one of the most basic training exercises, the plank, and turns it into a full-on gaming experience.