MLILY® WellFlex 1.0 12" Extra Firm Memory Foam Mattress - Double/Full

Comfort IQ™ · Scored on what actually matters

MLILY® WellFlex 1.0 12″ Extra Firm Memory Foam Mattress — Performance & Feel

Comfort IQ™ scores eight dimensions 0–10 from National Mattress's in-house testing + construction — the same scale on every model, so two beds compare on what actually matters. Results vary by body type, base, and room temperature.

The MLILY WellFlex 1.0 is an all-foam mattress built to keep movement where it happens — it earns an Excellent 8.5 for motion isolation, among the quietest, most undisturbed surfaces we test. Durability scores a flawless 10.0 on high-density foam over a high-density core behind a 10-year warranty, and pressure relief lands at a Very Good 8.4 as a 3-inch memory-foam layer cushions the shoulders and hips. Its Extra Firm (9/10) feel puts supportive foam right under you, which makes it a natural fit for back and stomach sleepers who want their hips held in line. Add a full 365-night trial and a fiberglass-free, CertiPUR-US certified build, and it's an easy bed to commit to.

Performance Scores

In National Mattress's in-house Comfort IQ analysis, the MLILY WellFlex 1.0 scores: Overall 8.39/10, Cooling 7.9/10, Pressure Relief 8.4/10, Motion Isolation 8.5/10, Edge Support 8.4/10, Responsiveness 7.7/10, Spinal Support 8.3/10, Durability 10.0/10.

Best For

Considerations

How It Performs — The Measured Detail

Feel & Firmness · 9/10 Extra Firm

The MLILY WellFlex 1.0 sleeps Extra Firm — a 9 out of 10 on our comfort scale — so you rest on top of the surface with supportive foam pushing back, not sinking into a plush cradle. A 3-inch memory-foam comfort layer takes the sharp edges off the shoulders and hips, but the 9-inch high-density support core underneath sets the tone: firm, even, and stable. Expect a grounded, consistent feel across the whole surface.

Cooling 7.9

Cooling is a Very Good 7.9 for the WellFlex 1.0, and it works at the surface rather than through the core. In-house analysis puts the peak surface temperature near 31.7°C — a touch below the direct-to-consumer field's 32.4°C median — settling back to about 27.6°C, right in line with the field. The catch is the climb: heat builds roughly 9.7°C over baseline, more than the field's 7.3°C, because an all-foam core simply breathes less than a coil bed. The Cooling Knit Fabric Cover and breathable surface foam carry the cooling load, so the top sleeps cool-to-neutral rather than icy.

Pressure Relief 8.4

Pressure relief is a Very Good 8.4, and the 3-inch memory-foam comfort layer does the work. It contours at the shoulders and hips — the spots that take the most load — giving real localized cushioning even though the overall feel stays firm. In-house analysis puts surface sinkage near 2.96 inches at the pressure points, on the deeper side for the class, so the foam cradles where you need it while the dense support core keeps you from sinking through. The result is targeted relief on a firm base rather than an all-over hug.

Motion Isolation 8.5

Motion isolation is where the WellFlex 1.0 shines — an Excellent 8.5. An all-foam build is the gold standard here: with no springs to carry a movement across the bed, a shift on one side is absorbed at the point of contact. On National Mattress's motion bench the peak transfer lands around 2.48 m/s²; because that bench reads at roughly half the scale of the direct-to-consumer method, it's best read on rank rather than the raw figure — and on rank it sits near the top. Movement settles in about 0.42 seconds, so a partner turning over rarely reaches your side.

Edge Support 8.4

Edge support scores a Very Good 8.4, but it is honestly an all-foam edge. With no coil reinforcement or encasement around the perimeter, in-house analysis shows the edge compressing about 4.74 inches under load — more give than a coil-encased bed and above the direct-to-consumer field's 3.75-inch median — so lying support right at the border rates only fair. You get a usable sleeping surface most of the way out, but sitting or sleeping on the very rim will feel the perimeter yield.

Responsiveness 7.7

Responsiveness is the WellFlex 1.0's most modest score at a still-Very-Good 7.7, and that is by design. A thick memory-foam surface recovers slowly: in-house analysis has it mostly back in about 1.26 seconds and fully recovered near 2.69 seconds — slower than the springier direct-to-consumer field, which sits closer to 0.3 and 0.8 seconds. Bounce is minimal, too — the surface compresses about 6.62 inches on impact and rebounds almost none (near 0 inches, for roughly 6.62 inches of total travel). The upshot is a gentle, melting feel that is supportive rather than athletic — the classic memory-foam trade-off, not a flaw.

Off-Gassing 8.0

Off-gassing rates a Very Good 8.0. The WellFlex 1.0 is built on CertiPUR-US certified foams — independently tested to strict low-VOC limits — and ships compressed in a box, so the initial smell is low and a faint new-foam scent typically airs out within 3 to 14 days as the bed expands and breathes. Unboxing in a ventilated room speeds it along.

Sleep Position & Body Weight Fit

Back and stomach sleepers are the natural fit for the WellFlex 1.0: the Extra Firm (9/10) surface and dense support core hold the hips level for neutral spinal alignment (spinal support 8.3), which is exactly what those positions need. Average and heavier sleepers will appreciate the on-top support and a firm core that resists bottoming out. Strict side sleepers — who need the shoulder and hip to give more — may find it firmer than ideal, though the 3-inch memory-foam layer softens the contact points. Combination sleepers who value stability over quick repositioning will feel at home.

At a Glance

Full construction and per-size dimensions are in the product description above. View 365-night trial details.

Frequently Asked