I have two new BPC 18 5.2Ah (these do not have a status light, are not airstream), but I would prefer to have a slimmer battery. Buying/selling does not make a lot of sense to me, but if you just happen to have the pair of good condition BPC18 3.1 Ah batteries (201790), and you'd prefer to have higher capacity, then maybe there's a win-win situation. We each pay our own shipping.