Bolt CBP-C1 Compact Battery Pack for Canon Flashes Extends Portable Flash Capacity | Up to 595 Flashes Per Charge Fast Recycle Times Up to 1.24 Sec | Thermal Switch Prevents Overheating Option of Using 4 or 8 AA Batteries Alkaline, Lithium or Ni-MH Batteries In The Box: AA Battery Magazine for Bolt Compact Battery Packs, Soft Case, Mounting Screw, Limited 1-Year Manufacturer Warranty