You mean the "fake battery" thing that would go into the AA compartment of the flash?? Hmm... I don't know... Unfortunately, I am a battery pack virgin. I have nothing to compare too... I need some sort of pack and I liked the idea of these because he boasted a lot of power and little frills... Hooked to my belt, I would probably not even be aware of the weight.... Its not grossley expensive... He seems to have specialized it for Vivitar 285's, which is what I uae, so, I may try it.