Harrods' biggest discount is on the Roidmi RS40, which is on sale for £359.02, down from £449. That’s a big saving of £89.98 or 20% off.

The RS40 is one of Roidmi's best models. It has excellent suction and a running time of up to 65 minutes. It's very light and manoeuvrable and can be used as a handheld for car interiors and on sofas.

The RS40's big hook is that it can mop and vacuum simultaneously. The mop is easy to use - you clip it straight on to the cleaning head with a magnetic attachment. It's useful for giving the kitchen floor a quick wash but even though this is one of the best vacuum cleaner mops I've tested, it's still no substitute for properly scrubbing the floor. 

The RS40 does, however, have some other, top-notch features. The first is the photosensitive LED headlight, which comes on when it's dark to illuminate the area you're vacuuming. It makes a huge difference to how well you can see (in fact, you often see a bit more than you'd like) and so it makes cleaning quicker and more effective.

The other feature worth noting is the magnetic charging dock. It's a small, round wall mount, so you don't need a big freestanding dock. When you click the vac into place, it'll begin to charge automatically. It seems like a small thing but cordless cleaners often require you to remember to plug them in in addition to docking them - and guess what? Sooner or later, that's something you'll forget to do. 

These are the sort of design features you'd expect to find on a £600 vacuum cleaner, like the Miele TriFlex. Roidmi's prices are already very competitive, so this discount is definitely worth going for.

Harrods has also slashed the price of the R20, from £399 to £335. That's £64 or 16% off. It has a lot of the same great features as the RS40, including the LED headlights and magnetic dock. What you won't get is the wet mopping functionality - but honestly, that's what I could most happily live without.

Finally, you can get the R10 for £215.01, down from £269: that's £53.99 or 20% off. The R10 has the fewest features of the three (there are no LEDs) but if you're after a slim, light, efficient cordless cleaner, you won't be disappointed.

Roidmi R10

To see which other vacuum cleaners we rate highly, have a look at our round-up of the best vacuum cleaners we've tested.