The verdict
The Havnby FlatCore for Model Y L is Havnby's air-and-foam FlatCore in a version sized for the six-seat Model Y L, and it is the only one of the 19 compared that is sized for that car. It has a built-in 12V pump and a shape that Havnby says takes the folded-seat slope out of the bed. At $699 / €659.95 it costs $150 more than the regular FlatCore, which holds its value score down. There are no owner reviews yet, so the case rests on Havnby's own specs and policies.
Who it's for
You'll love it if you own a Model Y L, want a bed shaped for its cargo area, and want the pump built into the mattress. Havnby advertises a 60-day trial, and you pay return shipping.
Look elsewhere if you drive a standard Model Y (this version lists only the Model Y L), want a USB-C pump rather than one that runs off the 12V socket, or want free returns.
What you'll notice
A shape for the seat slope
Havnby says the Y L's folded rear seats leave a slope and that this FlatCore is shaped to cancel it, claiming a 0° level surface. The shape deals with the seat fold only: no mattress can level a car parked on a slope. Havnby describes a foam top over a shaped air structure but does not say whether the foam sits inside the airtight chamber.
The published specs
It measures 200 × 130 cm and 19 cm thick, 7 cm longer than the regular FlatCore. It weighs 4.7 kg and packs down to 67 × 43 cm in its bag, which Havnby says fits the frunk or cargo area. Havnby's spec table gives 90 seconds to inflate and 100 to deflate (the page also says about 80 seconds elsewhere). A custom sheet is in the box.
What to watch for
Returns are not free
For a change of mind within the 60 days you pay return shipping (US buyers get a label with the cost taken off the refund; elsewhere you ship to a Havnby warehouse), original shipping is not refunded, and an opened mattress carries a $15 or $30 condition fee. The warranty is 3 years for orders since 1 June 2026, down from 5.
Delivery record
Havnby's Trustpilot rating is 3.6 from 19 reviews store-wide, and 43% are one-star, mostly about orders that did not arrive, tracking and slow support.
What owners report
Nothing yet. The product page has no reviews, and the owner quotes Havnby shows on it come from drivers of other vehicles, not the Model Y L. The Trustpilot figures above cover the whole Havnby store, not this mattress.
The bottom line
For a Model Y L owner this is the only purpose-made option in this comparison: sized for the car, shaped for the seat slope, quick to inflate, with an advertised 60-day trial and a 3-year warranty. The price is high, returns cost money and Havnby's delivery record is mixed. The creator code THEGREENES comes from The Greenes Go Wild YouTube channel and is not shown on Havnby's own pages; it took 10% off in Havnby's cart on 2 October 2026 ($699 → $629.10). Prices checked 1 October 2026.