Review on 🏃 MoKo Sweatproof Fitness Tracker Ankle Strap with Mesh Pouch - 2-Pack, Adjustable Band for Fitbit Inspire/Inspire HR/Charge 2/Charge 3/Alta/Alta HR/Flex/Flex 2/Vivosmart HR - Blue + Pink by Danny Robertson

Any of those ankle straps that attach the watch to the outside of the strap can only give you basic sleep results as contact lenses don't sit directly against your skin. For me it's better than nothing because RSI won't let me sleep with a bracelet. It's too chafing and annoying, so I prefer to wear it on my ankle. That's why I bought it, but I noticed another benefit I wasn't expecting: more accurate step counting! The watch uses the swinging arms to judge steps, but the ankle strap counts every step! I'm glad I bought it!