The garmin swim heart rate transmitter has the same features as hrm tri however it has a special non slip material keeping the monitor in place during push offs from pool walls or dives its never been possible to record heart rate accurately during swimming until now with the swim heart rate strap once on the belt is comfortable due to its seamless material and rounded edges the replaceable batteries x2 cr2032 will last up to 18 months if you are using the belt for 3 hours a week onc