I do not recommend mammotion, look elsewhere.
I discovered the brand at CES in vegas and was surprised by how mature the technology "appeared". I purchased their first generation device and it was solid for 10 months. Their power/charging systems are extremely poorly built, but thankfully their customer service handled the first few issues without pause. Sadly, after 15 months into the life of a nearly $3k device with a 3 year warranty, the true colors of mammotion are starting to shine. My device is a brick, customer service is useless, warranty is not being honored. Meanwhile the company is introducing new versions on what feels like a monthly basis. I do not recommend mammotion despite them starting off strong.