The Polar WearLink 31 Coded Transmitter & Chest Strap Heart Monitor is a reliable and efficient tool for monitoring heart rate during gym and training sessions. Designed by the reputable brand Polar, this HRM chest strap provides accurate heart rate measurements through its smart fabric technology. The transmitter is powered by batteries, making it convenient for use during workouts. The chest strap is designed for unisex adults and is worn on the chest to ensure proper monitoring of heart rate during physical activities. Perfect for fitness enthusiasts looking to track their cardiovascular fitness levels.