Features: 

• sends real-time heart rate and HRV data to compatible devices and apps
• up to 1 year of battery life
• comfortable and available in 2 sizes for an ideal fit
• durable and built to last with a 3 ATM water rating
• machine washable strap for easy cleaning

Sizing:

XS-S: Strap length: 22"–28" (56–72 cm)
Fits chest size 23.5–33.5” (60–85 cm)

M-XL: Strap length: 28"–42" (72–106 cm)
Fits chest size 31.5–47”(80–119 cm)