I think the BGBs were mainly spare NBC ground kit (about three suits, spare respirator canisters etc.) and our AR5 kit (charcoal coverall liners, socks, long-johns, green cloth helmet etc.). The long rectangular bags in AA62s picture are the cases for the actual AR5 respirators. There were also the Combi-pens and a stack of other stuff that would only be needed if the excrement/ventilator interface went fully brown. I can only assume that given the weight of the BGBs we were also supplied with depleted uranium diving boots and a full complement of lucky chain tensioners.