The Samsung 21700 40T is a vape battery with a nominal capacity of 4000mAh and a nominal voltage of 3.6V, suitable for various vape devices. It features a maximum voltage of 4.2V and a maximum continuous discharge current of 30A. This unprotected battery has a flat top style, with approximate dimensions of 21.1mm x 70.4mm and a weight of approximately 66.8g, making it compatible with many vaping starter kits and devices requiring 21700 size batteries.