Great lamp, poor specification of the required batteries for use with the extension tubes

I already have the design of the fairly similar T30S manufacturer and use of NCR18650B Panansonic with 3400 mAh. This works fine. The TN11S has an overall superior and refined impression, especially because of the variably usable extension tubes. And if I understand the accompanying description, the lamp creates 1163 lumens with only 2 x 18650 in extra time ... BUT: not so with the 18650ern that I have, the positive pole (+) that is "flat" is. For this lamp 18650 battery for operation in the extension are required, which have an elevated plus-pole. And unfortunately that is not sufficiently specified. Neither here nor on the manufacturer's website.