I’ve got a a few of them on different bikes, I only use protected cells, (3100 & 3400mah) the larger ones are a tight fit mind, the run time is insane compared to the battery that came with my Solarstorm
I picked mine up from a guy on ebay in Manchester a few months ago and he had a container full of lights and boxes
—- hes not on ebay anymore ? but i have this email….
puresystems@yahoo.co.uk may be worth a shot
ps i payed £45 for 3 boxes and a charger