All the produts are not battery packs, they are only empty boxes. For these style battery boxes, There are 4 versions, When place order, please choose the right version. The size is 43103410mm, it is for 50pcs of 18650 cells. The size is 43103430mm, it is for 52pcs of 18650 cells. Tthe size is 4098365mm, it is for 40pcs of 18650 cells. Tthe size is 58115420mm, it is for 65pcs of 18650 cells. Charge socket for Version B and A is default DC style. Charge socket for Version D is default RCA style. Version C case has two kind of charge socket for chocie. Version A and B pictures.