Specifications HRM 200 & 600 : 

• Sends accurate real-time heart and heart rate variability data to compatible Garmin 
  smartwatches and cycling computers, fitness equipment, and apps.
• Comfortable machine-washable strap is available in two sizes (XS~S and M~XL) for the most ideal fit for your body type.
• Up to 1 year of battery life with a user-replaceable battery for HRM 200 and up to 2 months of battery life with a rechargeable battery for HRM 600.
• Durable and built to last with a 3 ATM water rating for HRM 200 and for HRM 600, the water rating is 5 ATM.
• Understand how much you slow down when your foot hits the ground with step speed loss, and improve your running form with additional running dynamics, including stride length, vertical oscillation and ground contact time balance (requires compatible smartwatch) – for HRM 60
• During activities where you can’t wear a watch, like team sports, it will record the workout and sync data, including heart rate, calories, speed, distance and more, directly to the Garmin Connect app.
• Track daily metrics, including steps, heart rate, calories burned and more, and syncs that data directly to the Garmin Connect app – for HRM 600.
• Provides and stores accurate heart rate data during swim activities and syncs it to your
• compatible smartwatch after you save your workout – for HRM 600.
• For indoor track and treadmill runs, HRM 600 sends pace and distance to your compatible smartwatch.