The long life battery pack features high-low control. Pulse width modulation extends the battery up to 10 hours in the low setting, yet gives a full 2.5 hours on high. Can be used with vehicle battery with optional connector. Built-in charger allows you to fully recharge the battery in 12 hours. Purge the area on high for 10 minutes, then switch to low speed (low noise as well) and maintain fresh air for the whole work shift. Ideal for construction job sites to eliminate noisy petrol powered blowers.