CP-E4 Compact Battery Pack for 580EX II

The Canon CP-E4 Compact Battery Pack is an external power source designed to significantly reduce flash recycle times and extend the number of flash firings before battery replacement becomes necessary. This battery pack accepts the optional CPM-E4 rapid-change Battery Magazine, which holds eight AA-size batteries (alkaline, lithium, or Ni-MH) and enables quick battery swaps during critical shooting situations. The CP-E4 is compatible with Canon's 600EX-RT, 580EX, 580EX II, 550EX, 540EZ, 430EZ, MT-24EX, and MR-14EX Speedlites.

An improvement over the earlier CP-E3 model, the CP-E4 features enhanced dust and moisture sealing at contact points, bringing its weather resistance in line with the 600EX-RT and 580EX II Speedlites. The pack weighs 0.98 pounds (446 grams) when loaded with eight Ni-MH batteries, making it portable enough for studio work or on-location photography.