Features:-Compatible with Xiaomi Roborock S50/S51/S55 vacuum cleaner.-Made of high-quality lithium batteries, it has stable performance, is reliable and safe to use.-Built-in safety protection system to prevent voltage error, short circuit and internal overheating.Note:1. It is not necessary to ensure that the battery is fully discharged before charging every time;2. Once in a while (recommended within 2 months), you can do a deep charge and discharge under the control of the protection circuit to correct the battery power statistics (but this will not increase the actual capacity of your battery);3. If it is not used for a long time, it should be placed in a cool place to reduce the speed of its internal passivation reaction;4. If it is not used for a long .
eBay