The Modlite 21700 5000mAH Battery comes with 2 batteries per pack. Modlite adds a high quality protection PCB/BMS along with the button/nipple top in an ISO 9001 certified factory to all safety standards. A black wrap is put over the top to hold it together. FeaturesButton top Protected cellDimensions (including button): 21.7mm max diameter x 75.0mm max lengthNominal Capacity: 5000mAhMinimum Capacity: 4900mAhMax Discharge Current: 10ANominal Voltage: 3.6V (compatible with 3.7V)Full Charge Voltage: 4.2V