I bought this for my dad because hewanted to track his REM sleep but the Iwatch battery gets killed if you keep it on all night. Unlike some of the Fitbit models, the blaze has 'Sleep Stages' which gives you a more detailed overview on your sleep patterns. My dad loves this thing and says it syncs flawlessly with his iPhone X. The screen is actually bigger then the iwatch which he loves. Would definitely recommend. I purchased mine off Poshmark for a steal.