Physical specifications unit dimensions lxwxd tri 600 1420 x 30 x 12 cm swim 580 1450 x 38 x 12 cm weight tri 59 g swim 72 g module size 294 x 514 x 85 mm module weight tri 49 g swim 51 g size adjustment bi fold sizing range tri 600 1420 cm swim 580 1450 cm battery cr2032 battery life tri 10 months tri training 1 hour per day swim 18 months swimming 3 hours per week water rating 5 atm additional ant174 heart rate yes supports heart rate variab