About ST-139 The ST-139 chest strap is fully adjustable to fit all sizes. Easy to capture immersive footage from your chest by taking ST-139 chest strap with J-shaped bracket along. Easy to carry the ST-139 chest strap by the matching pouch. It is perfect for skiing, mountain biking, motocross, paddle sports or any outdoor activities where you want a more engaging, lower-than-the-helmet view of the action and hands-free operation. It will be your right-hand assistant. Welcome to buy!
