18650 batteries stand for 18mm diameter and 65mm length li-ion battery. They're the most popular battery type now. 18650 batteries are used in countless mechanical MODs and regulated MODs. We have famous Sony, Panasonic, SANYO, SAMSUNG, LG and Aspire batteries, especially, Sony VTC5/VTC4 and SAMSUNG 25R. They can provide 40A, 30A or 20A constant current, which will endow your MODs with enough power to have an amazing vape.