Robot Window Cleaner
Sticks to the glass and works its way across it.
$169.00
Free shipping, and 30 days to send it back for a full refund if it isn't right.
What it's good for
Finds its own path
It maps the pane and works across it in passes rather than wandering, so you aren't repositioning it every few minutes.
Stops at the frame
Edge sensors detect the window frame and turn it back, and a safety tether stays anchored while it works.
For the ones you dread
Most useful on the panes that need a ladder. On a low kitchen window a cloth is genuinely faster.