This is a single 21700 squonker or it can be configured as a dual 18650 non squonker. Wismec also gives you an extra direct output board that can be installed. Here are a few pics of the mod. It also comes with a magnetic plate that covers the squonk hole when you are not in squonk mode. Here is the battery compartment. There is a piece that converts the squonk bottle side to a battery compartment for an 18650. Kind of a cool concept. It's like a modular mod. review coming soon.