It is best to get an official Apple Battery Repair since the quality of third party Lithium batteries is extremely poor even when purchased from a reputable vendor such as OWC or iFixIt. If you insist on a third party Lithium battery, the get it from OWC or iFixIt. I know OWC has official resellers in other regions....not sure about iFixIt.
Keep in mind some Apple techs at Apple Stores or Apple Authorized Service Providers may refuse to service the laptop if it has a third party part installed. Technically Apple allows for repairs, but I have seen numerous posts on this forum over the years which say otherwise with repairs being denied even when the third party part is not the cause of the problem.
Also, with some Macs multiple internal components may need to be removed or at least loosened in order to replace the battery. I have seen a lot of posts on this forum where users reported their laptops no longer functioned correctly after attempting to replace the battery on their own because they accidentally damaged something (usually the Logic Board). There are a lot of fragile easily damaged cables & connectors. If you damage something, then the only option may be a much more expensive Apple repair.....assuming they will even touch the laptop with user inflicted damage along with a third party part. Even OWC recommends having their battery installed by a professional.