The above-mentioned item is a high-quality, compatible battery for your Mijia Roborock S51. It is an excellent replacement battery for your existing or defective Mijia Roborock S51. It can also serve as an additional spare battery for on-the-go use. Handling and charging are as usual, hassle-free with the standard power supply or charger. A high level of safety is provided by the protection electronics against overcharging and short circuits. The use of high-quality cells allows for a higher number of charge-discharge cycles, resulting in a longer lifespan for your new Mijia Roborock S51 battery. Quality is our top priority. This means that all batteries are new and unused. Our own quality assurance ensures a high standard of quality. Note: Unless we explicitly state that this is an original product, we supply a compatible product. This means it is in no way an original product from the manufacturer and is therefore not produced or recommended by them. All brand and product names are the property of their respective owners and are used solely for compatibility description.