Can't use your Adrenaline Shocker year round? We use Garmin Vivofit 4s as our timers. Easily remove the timer from the timer frame and insert it into this band to make other use of the timer in the off-season. Tons of widgets for fitness, etc. Comes with thick owners manual for Vivofit 4. Requires timer from Adrenaline Shocker (or other Vivofit 4).