Some are up to 6 years old, but every one i have tested so far is 3.7 volts. No bulging. They all have full cell protection, some have flying leads, some are solder points. There is at least 300 1070mah cells, 70 2700mah parallal packs, and honestly not sure, maybe 500 810mah, along with countless 1650mah cells with flying leads. Brand new, never used... i dont know that the hell to do with them. Anyone want some?