I got a Fitbit Charge 3 for Christmas last year (but I got it Black Friday-long story of procrastination) and it has an app that guides you through breathing exercises that I have found surprisingly helpful as I've had several panic attacks in the last week and all but one have calmed down some with this app. It's really simple, just inhale exhale and it shows how well you are following but after 2 minutes of focusing on it I have always been at least a little calmer. I'll be glad for this as I keep going through my klonopin taper in the next few months.