You get everything you need to make a 4P3S battery. This Bloc connects three groups of four cells in series and makes 10 volts. When you order more than one Bloc I assume you are going to assemble them into a larger battery and include everything you will need. If you are building more than one battery with your order the list will change slightly so let me know.
You can connect these 4P3S Blocs together to make larger batteries. For example, five of them will make a 4P15S battery.
All BatteryBlocs accept both new cells and cells with spot welded nickel strip. Salvagers, just cut the nickel strip and install the cells. No burs to file!
You can use BabyBloc Balancers, but it is overkill. A hobby Charger would be my recommendation.
Cells are for illustration purposes, not included.