Apple iPhone Duo Sets the Standard for Wide Foldables in 2025

Apple has once again defined the direction of the tech market with the release of the iPhone Duo this year. The device arrived in October and quickly became the benchmark for wide foldable smartphones. Competitors scrambled to respond, but Apple’s early development cycle gave it an edge despite later market entry.

Design and Build Quality

The iPhone Duo features a titanium frame, making it the most durable option among the four wide foldables compared. This contrasts with the aluminum frames used in the Galaxy Z Fold 8, Xiaomi 18 Fold, and Huawei Pura X Max. The device measures 117.8×84.1×11.3 mm when folded and 117.8×164.6×5.2 mm when unfolded, with a weight of 254 grams. This makes it the thickest and heaviest in the group, a trade-off for its premium materials.

The Galaxy Z Fold 8 is the thinnest at 9.7 mm when folded and weighs just 201 grams, giving it a clear advantage for one-handed use. Its dimensions are 123.9×81.9×9.7 mm folded and 123.9×161.4×4.5 mm unfolded. Samsung addressed past criticism of thick foldables by refining its engineering, resulting in the slimmest profile in the lineup.

The Xiaomi 18 Fold measures 117.8×83.6×10.7 mm folded and 117.8×163.8×5 mm unfolded, weighing 219 grams. The Huawei Pura X Max comes in at 120×85×11.2 mm folded and 120×166.5×5.2 mm unfolded, with a weight of 229 grams. All devices fall within a similar size range, but the Duo’s titanium build adds noticeable heft.

Camera placement differs across models. The iPhone Duo and Galaxy Z Fold 8 position their rear cameras on the side, causing slight wobble when placed on a flat surface in folded mode. In contrast, the Xiaomi 18 Fold and Huawei Pura X Max center their camera modules, eliminating this issue. However, all devices exhibit wobble in unfolded mode due to camera layout.

The Duo’s asymmetric design in folded mode may feel unusual to some users, particularly left-handed individuals. iOS elements like the Dock and controls are optimized for right-hand use, with no Action Button but a Camera Control feature. Volume buttons are placed on the top edge, resembling iPad layout. Xiaomi 18 Fold mirrors the asymmetric body but uses centered software controls via HyperOS, reducing right-hand bias. Huawei Pura X Max offers a balanced feel with rounded edges and a more neutral grip.

Durability is enhanced by Ceramic Shield glass on both outer surfaces and an IP68 rating for dust and water resistance. This level of protection is matched only by Google’s Pixel 10 and 11 Pro Fold among competitors. The Galaxy Z Fold 8 has IP48 rating, while Xiaomi and Huawei devices offer IP58/59. MagSafe support is exclusive to the Duo and Google’s foldables, enabling magnetic charging and accessory attachment.

Display Technology

Both outer and inner displays across the four devices are nearly identical in size. The outer screens are all approximately 5.4 inches, with slight variations: iPhone Duo at 5.4” (1:1.45), Galaxy Z Fold 8 at 5.4” (1:1.32), Xiaomi 18 Fold at 5.38” (1:1.47), and Huawei Pura X Max at 5.4” (1:1.46). Inner displays measure around 7.6 inches, with the Duo at 7.6” (1:1.42), Galaxy Z Fold 8 at 7.6” (1:1.58), Xiaomi 18 Fold at 7.58” (1:1.41), and Huawei Pura X Max at 7.7” (1:1.41).

All panels use OLED technology with a 120 Hz refresh rate. The iPhone Duo’s inner display features a nano-textured matte coating, which reduces the visibility of the fold line compared to the glossy screens on competitors. This is a deliberate choice to minimize visual distraction during use, though the crease remains present. The outer display remains glossy, consistent with industry standards.

Aspect ratios are close to 16:10, similar to MacBook screens, making them well-suited for multitasking and content consumption in both portrait and landscape orientations. The matte finish on the Duo’s inner screen is a unique differentiator, though long-term durability of the coating after six months of use is unknown.

Software and Multitasking

iOS on the iPhone Duo has been significantly reworked for the foldable form factor, avoiding a simple iPadOS port. System indicators like battery, Wi-Fi, and cellular signal are combined into a single icon positioned on the right side of the screen. Transitioning between outer and inner displays triggers a smooth animation that can be previewed on Apple’s website or simulated via a MacBook app.

The device supports Flex mode, allowing the hinge to lock at any angle like a MacBook lid. This enables partial unfolding for specialized use cases. In contrast, the Galaxy Z Fold 8 lacks Flex mode and relies on a clamshell mechanism that either fully opens or closes, with a kickstand engaging past 90 degrees. The Xiaomi 18 Fold and Huawei Pura X Max also allow free-hinge positioning without automated dampening.

Multitasking is limited to two apps simultaneously on the iPhone Duo, despite seamless performance. Competitors on Android often support three or more apps in split view, though real-world demand for such capability remains uncertain. App optimization is critical: only Apple’s native apps and a few third parties like Zoom and Netflix are currently well-adapted. iOS 27.1, which ships with the Duo, includes automatic layout adjustments for unoptimized apps, reducing letterboxing but requiring developers to update for full compatibility.

HarmonyOS on the Huawei Pura X Max presents a barrier to global adoption, as it lacks Google services and is difficult to use outside China. This limits its relevance in international comparisons, reinforcing the focus on the Duo and Galaxy Z Fold 8 as globally available options. Samsung’s One UI 9 benefits from years of foldable refinement, offering polished software experiences.

Performance and Hardware

The iPhone Duo is powered by the A20 Pro chip, outperforming the Snapdragon 8 Elite Gen 5 in the Galaxy Z Fold 8. The Xiaomi 18 Fold uses the Xring O3 processor, while the Huawei Pura X Max relies on the Kirin 9030 Pro. Samsung’s decision to use Qualcomm instead of its own Exynos chip is noted as a positive given historical issues with Exynos performance.

Despite the powerful chipset, the Duo does not include Face ID. Instead, it features a side-mounted Touch ID sensor, similar to iPads and Android foldables. Apple Watch users can also unlock the device via wrist authentication. The internal layout accommodates the Touch ID sensor, dual batteries, and other components, contributing to the increased thickness and weight.

Stereo speakers are positioned diagonally—top left and bottom right—unlike the Galaxy Z Fold 8, where speakers are side-mounted in unfolded mode. This arrangement improves audio balance. Apple claims the Duo dynamically redirects sound based on orientation, though real-world effectiveness requires testing.

Camera System

The iPhone Duo and Galaxy Z Fold 8 each feature a dual-lens rear setup: a 48 MP main wide-angle lens (26 mm, ƒ/1.6) and a 48 MP ultrawide lens (13 mm, ƒ/2.2, 120°). The Galaxy Z Fold 8 upgrades to a 50 MP main sensor (23 mm, ƒ/1.8, OIS, AF) and a 50 MP ultrawide (ƒ/1.9, 120°). Neither includes a telephoto lens.

In contrast, the Xiaomi 18 Fold offers a 200 MP main sensor (1/1.56", ƒ/1.7, 23 mm EFR, 7-lens, OIS), a 50 MP ultrawide (ƒ/2.4, 17 mm EFR, EIS), and a 50 MP telephoto (ƒ/2.8, 3.5x optical zoom, 80 mm EFR, OIS). The Huawei Pura X Max features a 50 MP main camera with variable aperture (ƒ/1.4–4.0, RYYB, 24 mm EFR, OIS), a 12.5 MP ultrawide (ƒ/2.2, 13 mm EFR, RYYB), and a 50 MP telephoto (ƒ/2.2, 3.5x zoom, 81 mm EFR, OIS).

Front-facing capabilities differ as well. The iPhone Duo uses a 12 MP Center Stage camera on the outer screen with a square sensor, enabling reframed video calls and selfies in any orientation. While the inner screen lacks a visible front camera to avoid distraction, its under-display quality is likened to old webcams on MacBooks. Users are advised to use the outer camera for selfies and calls. Video performance is expected to favor Apple, as Chinese competitors lead in photography but lag in video refinement.

Battery and Charging

Apple does not disclose exact battery capacity for the iPhone Duo but provides usage estimates: up to 24 hours of typical use, 44 hours of video playback on the outer 5.4-inch display, and 31 hours on the inner 7.6-inch display. This suggests battery life comparable to between the iPhone 17 Pro and 18 Pro. In testing, the iPhone 17 Pro lasted 8 hours 33 minutes under heavy use, so matching or exceeding that would be a strong result.

Charging supports 50% in 20 minutes with a 60W wired adapter and 50% in 30 minutes via 35W wireless charging. The device uses dual internal batteries to maximize space, enabled by the absence of a physical SIM card slot. Only eSIM is supported, even in the China variant—a continuation of the trend started with the iPhone Air.

In comparison, the Galaxy Z Fold 8 has a 5400 mAh battery with 30W wired and 25W wireless charging. The Xiaomi 18 Fold offers 4800 mAh with 45W wired and 20W wireless. The Huawei Pura X Max leads with 5300 mAh and 66W wired plus 50W wireless charging. Despite slower wired charging, the Duo’s efficiency and software optimization may yield competitive endurance.

Conclusion

The iPhone Duo establishes a new benchmark for wide foldable smartphones through its titanium build, Ceramic Shield protection, IP68 rating, MagSafe compatibility, and thoughtful software integration. While it is the thickest and heaviest device at 254 grams, its durability and premium materials justify the trade-off. The Galaxy Z Fold 8 remains the best option for portability at 201 grams and 9.7 mm thickness, but lacks the Duo’s build quality and ecosystem advantages.

Camera versatility favors Xiaomi and Huawei due to telephoto and variable aperture lenses, though the Duo’s video performance and software optimization may offset this. The matte inner display reduces fold visibility, a meaningful improvement over glossy competitors. Global availability and developer support give the Duo and Galaxy Z Fold 8 an edge over China-exclusive models running HyperOS and HarmonyOS.

Ultimately, the iPhone Duo succeeds not by leading in every spec, but by integrating design, durability, and software into a cohesive experience that redefines expectations for foldables. Its influence is already shaping the next generation of wide foldables across the industry.