1st generation iRobot Roomba vacuum cleaner.
Robotic vacuum is all a misnomer, these are actually robotic floor sweepers, the only vacuum function is there to capture the dust that the rotating brush flicks up & direct it in to the dust compartment.

95mm tall (will it get stuck under your sofa?)
330mm diameter (will it get stuck between chair legs?)

Works by bumping into things gently then turning round & going off in a different direction.

Parks itself back on its charger when it's finished or going flat.

No camera or WiFi etc capability, it's completely dumb, so at least it can't spy on you & send the details back to the manufacturers, which has been a persistent problem with newer robovacs.

We've had it for years but used it very little as we're not a tidy household, & it doesn't deal well with anything left on the floor (eg cables, socks, rugs, pets...) so it got relegated to sweeping the floor in our little conservatory, but that room is quite small, & we find that we just flick round it with a broom instead, so now it's just taking up space. (Or just gathering dust, to steal Tim Vine's perfect one liner)

It had a new (non-genuine, off the Internet) battery about a year ago.

It comes with the little battery-powered beacon that you place to keep it out of places where there's no physical barrier, eg top of a staircase. That beacon requires two HP2 aka D-cell batteries.

We even have the original box somewhere.
The only thing that I can't find is the lit3tool to make clearing fluff & hair from the rotating brush easier, but it's definitely around somewhere so if it hasn't turned up she you collect we'll pass it on when we find it. It's not essential.

Collection from Whitstable Road, Canterbury CT2.

Old robotic vacuum cleaner (St. Dunstan's CT2)