A:AnswerApple or Android both has Fitbit app. You dont necessarily need the app for the watch and you dont necessarily need a watch to use the app. The app has a lot of good features and I recommend downloading it whether you buy a watch or not. I use it a lot for tracking my daily hydration.
A:AnswerYes - I found other bands to fit Fitbit in Amazon. I'm not sure if there is a chain band available, but there are leather and pull on bands that are compatible to Fitbit.
A:AnswerYou can see your estimated oxygen variation through the night. You have to sync to the app for that level of data but you do not need a subscription.
A:AnswerIt starts monitoring when you go to sleep. The watch detects this based off the changes in your heart rate. If your not sleeping it's not going to monitor your sleep.
A:AnswerHi, GDubb. The Fitbit Inspire 3 and Fitbit Luxe have almost the same features. But you can wear the Fitbit Inspire 3 in clip mode, and it has up to 10 days of battery life compared to the Fitbit Luxe, which only has 5 days of battery life. For more information about the Fitbit Inspire 3, please visit this: https://support.google.com/fitbit/answer/14237921
For any additional questions and concerns, reach us at: https://goo.gle/contactfitbit