The Collar Power Bank is a 2850 mAh battery designed specifically for Vuzix Smart Glasses. It offers ten times the battery capacity of Blade Smart Glasses for 10 hours of run time under normal operation. The battery is worn around the neck to comfortably and conveniently extend device usage. It also provides pass-through audio from the Vuzix Blade Model 447 to headphones. Note: Vuzix Blade Model 494 cannot use the pass-through audio.