Apple's Foldable Is Dust-Tight. Samsung's Still Isn't.

The digit almost nobody reads

IP codes are defined by the IEC, and they are two independent tests wearing one label. The first digit rates protection against solids, on a scale that ends at 6. The second rates protection against water, on a scale that runs to 9. Marketing departments have spent a decade training buyers to look at the second number, because that is the one attached to the photograph of a phone in a swimming pool.

The number that separates the iPhone Duo from the Galaxy Z Fold8 is the first one. Apple's is a 6. Samsung's is a 4.

A 6 means dust-tight: nothing gets in, full stop. A 4 means the enclosure keeps out solid objects larger than one millimetre. One millimetre sounds small until you hold the scale against the things that actually kill phones. Beach sand passes under it comfortably. So does cement dust, flour, pocket lint and the grey fuzz that accumulates in a jacket lining. An IP4X device is protected against a paperclip, not against a beach.

Why a hinge is the hard part

A conventional smartphone is, mechanically, a sealed box. Adhesive runs the perimeter of the display, gaskets sit under the buttons, and acoustic mesh covers the speaker ports. Nothing moves relative to anything else, so every opening can be closed permanently.

A folding phone breaks that premise. It has a mechanism that opens and closes thousands of times a year, with parts that must slide past one another while the display bends around them. The seals have to move too, which means brush seals, sweeping gaskets and tolerances measured in fractions of a millimetre, and a gasket that sweeps is a gasket that wears. This is why foldables have spent years with water ratings that match ordinary phones and dust ratings that do not. Samsung has shipped IP48 across generations of the Fold, and the Galaxy Z Fold8 is still rated IP48 today.

Dust is not a theoretical complaint for these devices. It gets into the hinge, works into the mechanism and damages it from the inside, which is precisely the failure mode that teardowns of Samsung's foldables have been examining.

What Apple published, precisely

Apple puts a figure behind the water half of the rating: a maximum depth of 6 metres for up to 30 minutes. The company also lists a titanium frame, a titanium hinge cover and a ten-layer folding display among the Duo's durability features. That folding panel is the same one Apple had tested with a shortened Apple Pencil before setting the accessory aside, according to Bloomberg.

Apple is not alone at the top, and it is worth saying so plainly: Google's Pixel 11 Pro Fold also carries IP68. On this specific measure Apple has matched the best foldable rating on the market and beaten Samsung's. It has not invented a category.

The sentence in the small print

Apple's own caution is the most useful line in the whole specification: water and dust resistance "are not permanent conditions," and resistance can decrease as a result of normal wear.

That sentence describes how IP testing works. A rating is awarded to a new, undamaged unit in a laboratory, against fresh water, at a controlled temperature and pressure, held still. It is not a claim about seawater, chlorinated pools, hot showers, pressurised jets, or a device that has spent eighteen months being dropped on tile. Every drop, every thermal cycle and every hinge rotation degrades the seals that earned the certificate. On a foldable, one of those variables runs thousands of times a year.

There is a commercial consequence attached. Apple's hardware warranty does not cover liquid damage, and an IP rating on a spec sheet does not change that. The rating tells a buyer what the phone survived once, in a lab. It is not an insurance policy.

What it actually changes for a buyer

Three practical things follow. Dry the device before charging it, because a wet connector is a corrosion problem regardless of what the enclosure is rated for. Treat the rating as a margin against accidents, not as a permission to swim with the phone. And understand what dust-tightness does not cover: sealing keeps grit out of the mechanism, but it does nothing about abrasion on the outside. Sand caught between the two halves as they close will still scratch a folding panel that no amount of sealing protects.

The interesting test is the one that has not happened yet. Independent teardowns will open the hinge, and they will show whether Apple's seals hold up after the mechanism has been cycled, which is a different question from whether they held up on day one. The iPhone 18 Pro reaches buyers on 18 September; the Duo follows later, so that verdict is still weeks away.

For a first-generation product, matching the best dust rating in the category on day one is the harder half of the problem. Holding it after a year in a pocket is the half that decides whether the engineering was real.