The Sneaker is a convenient, compact vape pen battery. It works with commonplace 510 threaded vape cartridges; most of the cannabis cartridges on the market will fit in The Sneaker. When you have run the charge down on this device, the charger is built in - plug the battery itself into a USB-A port and give it time to juice up again. Then, you can hang it around your neck or from a keychain using the convenient loop provided. Three inches long; maybe not much longer than your cartridge.