​ ​To our device like Laptop, Gaming Laptop and MacBook, in each spare parts like the batteries and Adapter  will get aged or damage. For example the Laptop have been used for many years so the batteries will not work as it is normal. It will be fast to drained or not consuming charging. So the laptop may gonna work only thru the connection of the charger. At this point, it may need to replace a new one. So will be base with the Model Number at the back of Laptop. Similar with the image above that has red box signed. 

Together with Macbook if need to replace the batteries whether its get aged or got damage from water spilled or got short circuit and had burn inside or any accident may happened that will affect on the battery. The most important to know of getting the exact batteries or even adapter is the Model number will get at the back of Macbook. Showed on the image below.

So before will purchase any spare parts that got damage and need to replace. Always look for the model number that may seen at the back of the Laptop or Macbook.