The verdict
The HEST Dually has the highest comfort score of the pure-foam mattresses in this comparison. Its two-density construction puts softer memory foam over a firmer base. At $529 to $679 depending on size, and 9 to 13 kg, it's also one of the heaviest and bulkiest options in this comparison, and it was designed for truck beds, not Tesla cabins. The comfort score, 8.5, is one of the highest here. The fit score, 5.0, is the lowest of all 19. You need to decide which matters more for how you actually camp.
Who it's for
You'll love it if you already own a truck and want one premium foam mattress that works in both vehicles, or if you prioritise foam comfort above everything else and you're willing to manage the weight and bulk. Side sleepers who spend multiple nights out get two layers of foam for pressure relief, though at 10 cm it falls short of this site's 15 cm side-sleeper rule and some report bottoming out.
Look elsewhere if your only vehicle is a Tesla. The HEST Dually does not address the seat-fold slope, doesn't pack small, and at 9 to 13 kg it's a serious load to move in and out of a Model Y. No reviews from Tesla owners could be found, and HEST ships within the United States only.
What you'll notice
Two foam densities
HEST describes a softer contouring layer over a firmer base. For side sleepers the firmer base is meant to stop hips and shoulders bottoming out, though some owners report that they still do. Setup is a simple unfold with no pump or inflation involved.
Weight and bulk are the real cost
At 9 to 13 kg depending on size, and folding to a sizeable package, the HEST Dually is not a lightweight camping solution. At that weight, expect a two-handed lift in and out of the car. If your camping style involves frequent moves between campsites or tight boot space, that weight adds up fast.
Marginal Tesla fit
The HEST Dually was engineered for truck beds, which have a different geometry to a Tesla cargo floor. It comes as a plain rectangle, 127 to 152 cm wide and 163 to 198 cm long depending on size, so it isn't cut to match the Model Y cabin, and it does nothing for the seat-fold slope. No Tesla owner reports could be found to show how it sits in the car. You're not sleeping on a Tesla-optimised surface; you're sleeping on an excellent truck mattress that was not shaped for your car.
No pump required
The absence of inflation is one of the HEST Dually's practical advantages. There's no pump to charge, no valve to locate in the dark, and no waiting for inflation. You unfold it and it's ready in about a minute. That simplicity is genuinely useful on a tired late-night arrival.
What to watch for
It doesn't solve the slope
Nothing in the HEST Dually's design addresses the seat step (the step between the folded rear seatbacks and the boot floor). There's no floor-flattening geometry, no wedge, and no inflatable layer you can adjust to compensate. On any slope, you'll want leveling blocks under the car's wheels.
Storage requires dedicated space
HEST publishes no Tesla sub-trunk fit, and folded the Dually is too large to slip into a small corner of the boot. If you keep camping gear in your car between trips, this occupies meaningful space. In a Tesla, plan to load it for each camping trip rather than leave it in the car full-time.
The bottom line
The HEST Dually is the right answer to a specific question: which pure-foam mattress scores highest on comfort in this comparison? If that's your question and you're willing to manage the weight, bulk, and marginal Tesla fit, the answer is this. If your question is what's the best sleep system specifically for a Tesla, one that handles the seat-fold slope, packs into the sub-trunk, and is optimised for the cabin geometry, the HEST Dually is not it. The two questions have different answers, and the HEST Dually only wins the first one.