Camera SF-18 Flash Battery Pack CP-E4 for Canon 580EXII, 580EX, 550EX, MR-14EX, MT-24EX and Yongnuo YN-560 (Discontinued by Manufacturer) Protective Case 1/4'' Thread Screw Efficent Performance Maximum of 15 consecutive shots without break or risk of overheating This Battery Pack can hold 8 AA-type batteries