The milwaukee m18nrg 902 energy pack contains the following 2 x 18 volt m18 b9 90ah redlithium ion slide battery packs fitted with redlink intelligence and overload protection which prevents the user from damaging their tools it has a temperature control cell frame that keeps the battery at an ideal temperature range to provide maximum life there is a waterproof protection barrier a rubber overmould and shock responsive separators to protect the battery from damage with individual cell monitor