The ProTek RC 1S USB LiPo Charger was developed specifically for ProTek RC PTK-5197 and PTK-5550 1S LiPo transmitter batteries. Have you found that your charger is not fully peaking your transmitter packs? Some high end chargers struggle to put a full charge on these batteries due to the way the charger measures resistance, and no matter what you do, they will not peak at full capacity. This small and affordable option solves that problem. With a fixed 1 amp charge rate, LED charge indicator, and easy USB power access, this easy to use charger will ensure your JR connector equipped 1S transmitter batteries get a full charge each and every time.