26650 batteries refer to li-ion batteries with 26mm diameter and 65mm length. They can provide more battery capacity and higher current than 18650 batteries. They're used with mechanical MODs or regulated MODs. You can use 26650 batteries with mechanical MODs, such as HADES, Deceptions, Cartel, Manhattan. Moreover, you can also with it with ENCOM TNT80W or any other MODs support 26650 batteries. You'll have a perfect experience with it.