Thank you for viewing! These are new Tamiya Neo Champ batteries, broken in using a Kyosho SPEED HOUSE Multi-Cell Charger EVO (72012). Each set of batteries has been conditioned to have similar internal resistance, capacity, and discharge curves. There are two sets (4 batteries). * Each set will be marked with a sticker. * As the batteries are used, the internal resistance may change, so it may be better to switch the pairs. Neo Champ batteries, when new, do not charge to their full capacity, and their discharge capacity tends to be low. Also, the discharge voltage is low, so breaking them in is essential for use in races, etc. These batteries have been conditioned from new, starting with low current, then medium current, and finally high current, to develop the "habit" of delivering high current when used in Mini 4WD cars. They can also be charged to their full capacity, and can discharge about 90% of their full charge. If you have any questions, please comment. Thank you. * It may take 4-7 days to ship as the break-in process takes time. * The values of internal resistance and capacity vary depending on the charger and measurement method used. The batteries are assembled based on "low variation" within the set. * Performance may not be achieved depending on the usage method and charger, so please refrain from purchasing if you expect excessive performance. Rechargeable battery Battery NEO CHAMP