ANTHBOT
M9
Rated for 0.25 acres and 45% grade — that is 24.2°, not 45°. On a real lawn, once you allow for borders and travel paths, plan on about 0.2 acres.
What it handles
Two-wheel drive, which caps how steep it can work. That covers rolling ground, but not a bank you would struggle to walk up.
Navigation includes vision or LiDAR, so it keeps working under tree cover where satellite-only machines lose their fix.
If your ground is steeper
These are rated for a similar area but hold more grade than the M9’s 45%.
Cross-shopped with
Rated for a similar area, at the same grade or less.
How confident we are
Cross-checked against the manufacturer and at least one other source.
Confirmed 45% and 1000 sq m (0.25 acre) on anthbot.com. Conflict to watch: some Amazon listings and the manual intro say 0.3 acre, a figure ANTHBOT publishes nowhere on its own site. The manual spec table has no working-area row, so no source here is fully authoritative.