Amazon.com : JJC Rapid Flash Fire Recycling External Flash Battery Pack for Speedlite Canon 600EX II-RT,580EX II,550EX,540EZ,430EZ, Yongnuo YN600EX-RT,YN560IV II, Nissin MG8000 Di866 Mark II for Canon as CP-E4N : Electronics
Amazon.com : Godox External Flash Battery Pack Cable Compatible with Canon 430EZ, 540EZ, 550EX, Cannon 580EX, 580EX II and other flash model with same type of input power port. : Camera Flash
Canon CP-E4 Compact Battery Pack
Pixel TD-381 battery Power Pack for for Canon Speedlites 580EX II, EX580, EX550, MR-14EX,MT-24EX, extremely stable fast recycle time 1.24S