Many devices monitor your heart rate these days, but few are as accurate as ones that stick to your chest, one way or another. Chest straps can be uncomfortable and are usually only worn for short periods, but the AmpStrip is small and light enough to stay on your skin for days at a time. It glues on to you with a special adhesive that is bio-compatible to ISO 10993, and is “designed to stay on under the most rigorous conditions, including pool and ocean workouts and strenuous whole body efforts for 3 or more days.” In this fashion you can have accurate heart rate measurements throughout your day; a 3-axis MEM’s accelerometer detects your movements, and a proximity Thermistor detects skin temperature. This data is important to athletes who wish to push their boundaries in a safe and efficient manner. The AmpStrip’s 20mA battery lasts up to 7 days without a charge, and integrated storage allows you to untether from your phone for up to a day. It’s a $135 pre-order, with a ship date of August.