Energizer Industrial C batteries are the exact same batteries offered to consumers (with the silver labels) except they are specially priced for government and commercial buyers.
 
Most popular long-lasting power source
Very good shelf-life: up to 10 years at 21°C
Lower initial cost compared to Lithium and NiMH Rechargeable battery systems
Suitable for use across all types of devices
72 C batteries
1.5 Volts 8350 mAh