Thank you. Wasn’t sure if that was a type of battery, and I didn’t think that a Google search on just a number would be very successful in pinning it down.

An 18650 battery is a type of lithium-ion rechargeable battery123. The name 18650 comes from its dimensions: it is 18mm in diameter and 65mm in length. The battery has a nominal voltage of 3.7v12and a capacity range from 1800mAh to 3600mAh12. 18650 batteries are commonly used in electronic devices such as laptops and flashlights, as well as in electric vehicles and other high-power applications.