Proscenic Q20 Plus

Suction in pascal, as the maker measures it. More pascal helps on carpet, but it says little about how well the robot picks grit off a hard floor.

A brush that guides hair to the side instead of letting it wind around the shaft. It saves the cutting work in homes with long hair or pets.

The side brush swings out in a corner or along a kickboard, so the dust there is swept in too. On this model: Assumed, not a stated fact: the maker's full specification does not name it, so we take it as no.

How the mop is built: flat pads, two spinning discs or a roller. Discs press harder on dried-on dirt, a roller rinses itself while it works.

The pad slides out along a wall or a kickboard, so the last few centimetres are mopped as well. On this model: Assumed, not a stated fact: the maker's full specification does not name it, so we take it as no.

The robot leaves the mop at the dock before it vacuums a carpet, so the carpet never gets wet. On this model: Assumed, not a stated fact: the maker's full specification does not name it, so we take it as no.

The robot returns to the dock during a run to rinse the mop, instead of pushing dirty water around. On this model: Assumed, not a stated fact: the maker's full specification does not name it, so we take it as no.

How much clean water the robot carries. It sets how long it mops before a refill, which a dock does by itself.

The robot or its dock works with steam. It loosens dried-on dirt and grease, or washes the mop hotter than water alone. On this model: Assumed, not a stated fact: the maker's full specification does not name it, so we take it as no.

The dock empties the robot’s dust bin, usually after every run. You only empty the dock’s bag or bin.

The dock collects dust in a bin instead of a disposable bag. No bags to buy, but you empty it yourself.

How the robot maps your home and follows that map. Lidar measures with a laser and works in the dark, a camera looks along and recognises more.

How the robot sees loose things on the floor, such as cables, socks or a pet accident. A camera with depth sensing sees more than a bumper that reacts on contact.

The highest threshold the robot takes, as the maker states it. Measure your own: the step into a bathroom or onto a balcony is often higher.

An extending leg or wheel that carries the robot over a high threshold. Without one it usually stops at about 2 cm. On this model: Assumed, not a stated fact: the maker's full specification does not name it, so we take it as no.

How many floor plans the robot keeps. With more than one it knows which floor it is on when you carry it up or down the stairs.

An arm on the robot that picks up small loose things such as socks, so they are not in its way. On this model: Assumed, not a stated fact: the maker's full specification does not name it, so we take it as no.

How tall the robot is. It decides whether it fits under your sofa, bed or cabinet.

How much dust the robot holds before you empty it. It matters less with an auto-empty dock, which empties the bin after every run.

The noise in decibels while cleaning, in the setting its source names: makers mostly give the standard setting, shops often the highest. 65 dB is like a vacuum at half power, 55 dB like a conversation. Emptying by the dock is louder and listed on its own.

The capacity of the battery. It hints at the runtime, but how much the robot draws counts just as much.

How long the robot cleans on one charge, at its quietest setting. After that it recharges and carries on where it stopped.

Matter is the standard that lets devices from different makers work together. With it you can run the robot outside the maker’s own app. On this model: Assumed, not a stated fact: the maker's full specification does not name it, so we take it as no.

Which voice assistants the robot works with, such as Google Assistant or Alexa.

The warranty the maker gives in Germany. Consumer law here stands apart from it and can last longer.