NEEWER PB3000II 3000mAh Portable Flash Power Box backup for CANON 430EX 540EX 550EX 580EX 580EX II Suitable for: CANON 430EX 540EX 550EX 580EX 580EX II Flash times: 1200 times full power (test with Canon 580EX II) Adopt CPU to control circuit Quick recycling Use high energy lithium cell