It’s a dirty cheap 6-13s BMS without balancing, need to check cell voltages from time to time.
Unfortunately there is no small 12s BMS with balancing available so I try this one for science (no space). According to the diagram B12+ and B13+ of the BMS are connected to B12+ of the battery (for 12s). But if this BMS works or not I don’t know yet 
I think it’s best to balance charge the battery first before using this BMS.