TORO 60V Max Revolution Backpack :

Tough and comfortable to wear, the backpack holds two FlexForce Power System™ batteries to extend your range, and includes advanced LED battery diagnostics.

• Removable battery system with space for up to two high capacity batteries means you’ll always have power at hand.
• Interchangeable arm cannon or powerlink tether.
• Comfortable and sturdy backpack system keeps jobs moving all day with less fatigue.
• Integrated carrying handle for easy maneuvering.