Hi bros and sis out there, really need your advice. I am currently using a Sigma 500 DG ST Flash. During one of my friend's wedding, I saw the photographer using the same flash, but with a additional attachment to the battery compartment which he said is to help with the battery recharge rate. I am unable to talk to him much as he is busy running around and I am too drunk to ask him later.

I am looking for the attachment as I have always encounter problem with the charge rate of my flash, just can't get it charge up and ready for my next shot. I had tried using all kinds of battery, but can't last the whole shoot and my wallet content also can't substain . Can anyone advise me on this? Thank you!!