Some batteries don't have a Battery Management System (BMS) builtin and instead have the BMS built into the charger itself. Saves a few dollars as you only need the BMS in the charger and not multiple batteries.
You may have read warnings, "only charge on the charger that came with this device". It's a bit of a crappy idea, there are serious risks to unmanaged charging of lithium batteries. These are the sorts of charging system that have been responsible for battery fires.
Every ToolBattery rebuild has the BMS checked and its performance measured. If there is any doubt regarding the a BMS not performing to specification, it is replace with a new one. The replacement BMS(s) ToolBattery use are designed for each battery set, they all have heat sensors to protect cells from overheating, larger batteries have multiple heats sensors for each cell group.
ToolBattery have BMS modules with built in Bluetooth for larger battery sets that allow you to monitor your battery's health from the inside of the battery pack.
ToolBattery rebuilds are safe to charge on any compatible charger without risk to the cells, like Mark's beauty, the BMS is on the inside.