ACEBEAM IMR21700NP-510A is a new generation high performance cell with a maximum capacity of 5100mAh and a USB-C charging port to remove the need for an external charger. This powerful battery has improved performance, and superior energy density compared to previous 18650 batteries. An ideal companion for the L18 or L19 tactical flashlight from ACEBEAM, an extra 21700 is a great back-up battery to have on hand, as more electronic products and ACEBEAM flashlights will utilize this battery.