adidas Heart Rate Monitoring Techfit Shirt 86% Polyester/14% Elastane Imported This adidas smart shirt features exclusive heart rate sensing technology knit directly into the fabric, no chest strap required Knit-in heart rate sensing fabric accurately and comfortably captures heart rate data during your workout adidas Techfit delivers second-skin fit, non-slip performance, quick dry fabric and is machine washable Use with your favorite heart rate monitor (HRM) pod to track your heart rate and reach your fitness goals Compatible with snap-on transmitters from leading technology brands, e.g. Polar, Garmin, Runtastic, Wahoo Fitness, Zephyr, etc