From Mystic

Take your valuables with you as you ride. The Fidlock closure ensures your phone, keys, and other essentials stay completely watertight, even in tough conditions. Though designed for kite and windsurfing, this pocket is versatile enough for most water-based activities or to keep your belongings safe from rain on your next adventure. With an easy-to-lock mechanism and a super strong, adjustable cord, you'll be reaching for it time and time again.