The Digitsole Warm Series is a heated insole equipped with Bluetooth. The insole works with an innovative app for iOS or Android. The novel smart heating technology regulates the temperature between 30°C and 45°C using a thermostat. The app also includes an activity tracker that measures your step count, distance traveled, and calories burned using the insole. It's important to note that this special insole for sports and leisure uses a durable lithium-polymer battery that is charged via Micro-USB. ARCH Support. FLEX Zone. Antibacterial fabric.