・ The maximum capacity of 18650 lithium-ion batteries is 3500mAh. 　18650 rechargeable batteries sold with a higher capacity may have a different actual capacity. 　If the capacity is low, the lighting time will be shorter. Please be careful. ・ 18650 2600mAh with a protection circuit. It prevents over-discharge and overcharge. 　Because it has a protection circuit, you can use it safely and with peace of mind. This product complies with the Electrical Appliance and Material Safety Law enforced by the Ministry of Economy, Trade and Industry. We also conduct a full inspection. PSE mark is indicated. (Products listed without the PSE mark are illegal. Please be careful as they are dangerous.) As a result of measuring 18650 batteries sold elsewhere, the capacity was not as stated. If the capacity is low, the lighting time will be shorter. ＜Product Specifications＞ ・ 18650 lithium-ion rechargeable battery Built-in protection circuit (with protection circuit) Dimensions: 69mm (length) x 18.2mm (outer diameter) Nominal voltage: 3.7V Nominal value: 2600mAh ・ USB type rapid charger, two-port type Built-in overcharge protection circuit (safe and secure) (If you charge a lithium-ion rechargeable battery with a charger that does not have an overcharge protection circuit, there is a risk of explosion. Please be careful.) Size: Overall length 105mm x width 50mm x height 28mm Weight: approx. 73g Input: 5V 1A Output: 4.2V 1A Input terminal: USB port USB-microUSB cable: 80cm USB charging AC adapter The USB type rapid charger can be charged with smartphone chargers or USB devices on a computer. If you don't have one, you can use this product to charge from a household outlet. ↑↑↑The above text is a copy of the product description when I purchased it on Mercari about a year ago. I have only charged it about 5 times. One is unused.