FEATURES: The three constant heat power settings, and thefourth Power Boost setting, can be selected usingthe Power button on the battery packs or very convenientlywith the HOTRONIC Heat app via a Bluetooth-enabled smartphone 6000 mAh capacity offers a category-best 24 hoursof constant heating power High-performance Lithium-Ion battery with USBrecharging cable Cambrelle covers for easy integration with all typesof insoles, whether preshaped or customized The HOTRONIC Heat app provides an overview ofthe current charge status and heating levels. Theapp is available free of charge from the App Storeand Google Play Store