This single Therm-ic C-Pack 1700B battery offers the longest runtime in the lineup—up to 17 hours—and supports both manual and Bluetooth app control. Great as a spare or replacement for your C-Pack 1700B set. Best attached to the tongue loop of your ski boot liner.

• Manual control or Bluetooth app with 10 heat levels
• Motion sensor and eco mode via app
• Bluetooth levels mirror manual output: Manual 1 = App Level 3, Manual 2 = App Level 6, Manual 3 = App Level 10