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Apple iPhone 4 vs Apple iPhone Duo

Every spec side by side, from each maker's published figures.

Better figure, where one is clearly better

AppleiPhone 4AppleiPhone Duo
Overview
ReleasedJune 2010Coming 23 October 2026
Display
Screen size3.5″7.6″
Resolution960 × 6402670 × 1878
Sharpness330 pixels per inch430 pixels per inch
PanelLCDLTPO OLED
Refresh rate60 Hz120 Hz
Peak brightness500 nits3,000 nits
Cover screen–5.4″, 2034 × 1398, 120 Hz
Display typeRetina display; 3.5-inch (diagonal) widescreen Multi-Touch displaySuper Retina XDR OLED folding display (inner) with nano-texture finish and wide-angle OLEDs; Dynamic Island on both displays
Pixel density326 ppi430 ppi (inner); 460 ppi (outer)
Brightness detail500 cd/m² max brightness (typical)Both displays 1,000 nits max (typical); 1,600 nits peak (HDR); 3,000 nits peak (outdoor); 1 nit minimum
Always-on display–Yes
Screen protectionAluminosilicate glass front and back; fingerprint-resistant oleophobic coating on front and backCeramic Shield 2 on the outer display, Ceramic Shield back; inner display has a scratch-resistant coating over a nano-textured custom polymer cover layer, high-strength glass above and below the panel and a titanium plate beneath
Display features800:1 contrast ratio (typical)ProMotion adaptive refresh up to 120 Hz; HDR; True Tone; Wide colour (P3); Haptic Touch; 2,000,000:1 contrast ratio (typical); anti-reflective coating; Apple Pencil (USB-C) support on either display, which Apple says is coming later in 2026
Cover screen–5.4-inch Super Retina XDR OLED, 1398 x 2034 at 460 ppi, ProMotion up to 120 Hz, same aspect ratio as the inner display; measured as a standard rectangle the screens are 7.58 and 5.36 inches
Performance
ChipA4A20 Pro
Memory512 MB–
Storage8 GB, 16 GB, 32 GB256 GB, 512 GB, 1 TB, 2 TB
CPU1.0 GHz Cortex-A8 (GSMArena); 512 MB of RAM (iFixit)6-core CPU with 2 super cores and 4 efficiency cores; 2-nanometre process
GPUPowerVR SGX535 (GSMArena)7-core GPU with Neural Accelerators; hardware-accelerated ray tracing
AI engine–Dual 16-core Neural Engine
Cooling–Custom vapour chamber connected directly to the chip package; up to 35% better sustained performance than iPhone 17 Pro (Apple)
Cameras
Main camera5 MP48 MP
Ultra wide cameraNone48 MP
Telephoto cameraNoneNone
Optical zoomNoneNone
Front camera0.3 MP12 MP
Main camera5-megapixel still camera with LED flash and tap to focus48MP Fusion Main, 26 mm, ƒ/1.6 aperture, sensor-shift optical image stabilisation, Hybrid Focus Pixels; 24MP and 48MP photos
Ultra wide camera–48MP Fusion Ultra Wide, 13 mm, ƒ/2.2 aperture, 120° field of view, Hybrid Focus Pixels; 24MP and 48MP photos
Front cameraVGA-quality photos and video at up to 30 fps12MP Center Stage camera (outer), ƒ/2.2 aperture; under-display FaceTime camera in the inner display, ƒ/1.8 aperture, 1080p video (resolution in megapixels not published)
Zoom–12MP optical-quality 2x Telephoto (52 mm, ƒ/1.6) from the Main camera; 2x optical-quality zoom in, 2x optical zoom out (4x optical-quality zoom range); digital zoom up to 10x (6x for video)
Video recordingHD (720p) up to 30 fps with audio4K Dolby Vision at 24, 25, 30 or 60 fps, and at 100 or 120 fps on the Fusion Main camera; 1080p Dolby Vision up to 120 fps; Cinematic mode up to 4K Dolby Vision at 60 fps, with effects applied after capture; Action mode up to 2.8K Dolby Vision at 60 fps; slo-mo 1080p up to 240 fps and 4K Dolby Vision up to 120 fps (Fusion Main); Dual Capture up to 4K Dolby Vision at 30 fps; macro video; HEVC and H.264
Front video–Outer camera 4K Dolby Vision at 24, 25, 30 or 60 fps, Cinematic mode up to 4K Dolby Vision at 30 fps, slo-mo 1080p at 120 fps; inner camera 1080p at 30 or 60 fps
Camera featuresTap to focus video or still images; photo and video geotaggingSmart Take; Duo Preview and Kid Cue on the outer display; Photographic Styles 3; smart focus tracking; Photonic Engine; Deep Fusion; Smart HDR 5; Night mode; next-generation portraits with Focus and Depth Control; panorama up to 63MP; 48MP macro photography; True Tone flash; sapphire crystal lens cover; Camera Control; HEIF and JPEG; no Pro controls
Battery and charging
Battery1,420 mAh–
Video playback (maker's claim)Up to 10 hoursUp to 31 hours
Wireless chargingNoneUp to 25 W
Battery life detailTalk time up to 7 hours on 3G or 14 hours on 2G; standby up to 300 hours; internet use up to 6 hours on 3G or 10 hours on Wi-Fi; video playback up to 10 hours; audio playback up to 40 hours; 3.7 V, 1,420 mAh (iFixit)Two lithium-ion batteries, one in each half, managed as one; up to 24 hours typical use (equal use of both displays); video playback up to 31 hours on the inner display and 44 hours on the outer; streamed video up to 26 hours inner and 37 hours outer
Wired chargingCharging via USB to a computer or power adapterUp to 50% in around 20 minutes with a 60W-capable USB-C adapter or higher (sold separately); Apple doesn't give a maximum wattage
Wireless charging–MagSafe and Qi2 up to 25W; up to 50% in around 30 minutes with a 35W adapter or higher and a MagSafe Charger
Design
TypeStandardFoldable
Weight137 g254 g
Thickness9.3 mm11.3 mm
Height × width115.2 × 58.6 mm117.8 × 84.1 mm
Water and dust resistance–IP68
Stylus–Yes
Size unfolded–117.8 × 164.6 × 5.2 mm (height × width × thickness)
MaterialsAluminosilicate glass front and back with a stainless steel bandGrade 5 titanium enclosure with a mirror-polished finish (85% recycled titanium); 3D-printed titanium hinge cover with a micro-blasted finish; Ceramic Shield back
ColoursBlack, whiteStar White, Night Sky
ButtonsOn/off, sleep/wake; ring/silent; volume up/down; HomeSide button with Touch ID; Camera Control; volume up/down; no Action button
Water resistance detail–IP68 (maximum depth of 6 metres up to 30 minutes) under IEC standard 60529
Biometrics–Touch ID fingerprint sensor in the side button
SensorsThree-axis gyro; accelerometer; proximity sensor; ambient light sensorTouch ID; barometer; high dynamic range gyro; high-g accelerometer; proximity sensor; four ambient light sensors
Speakers–Built-in stereo speakers
Microphones–Built-in microphones; Voice Isolation and Wide Spectrum modes
Software
Operating systemiOSiOS
Software at launchiOS 4iOS 27.1 (Apple's press release; the spec page lists iOS 27)
AI features–Apple Intelligence; Siri AI (beta, English at launch, not initially available in the EU); Siri Camera mode through Camera Control
Safety features–Crash Detection
In the box–iPhone Duo, USB-C Charge Cable (1 m); no power adapter
Connectivity
Satellite messaging–Yes
Mobile networkGSM model: UMTS/HSDPA/HSUPA (850, 900, 1900, 2100 MHz) and GSM/EDGE (850, 900, 1800, 1900 MHz); CDMA model: CDMA EV-DO Rev. A (800, 1900 MHz)Apple C2 modem; 5G (sub-6GHz) with 4x4 MIMO; Gigabit LTE with 4x4 MIMO; UK model A3720 (US model A3447 adds mmWave)
SIMMicro-SIM (GSMArena)Dual eSIM only (two active, eight or more stored); no physical SIM
Wi-FiWi-Fi 802.11b/g/n (802.11n 2.4GHz only)Wi-Fi 7 (802.11be) with 2x2 MIMO; Apple N1 wireless networking chip
BluetoothBluetooth 2.1 + EDRBluetooth 6; Thread
Ultra Wideband–Apple second-generation Ultra Wideband chip
NFC–NFC with reader mode; Express Cards with power reserve
Satellite features–Emergency SOS via satellite; Roadside Assistance via satellite; Find My via satellite; Messages via satellite in the US
USB30-pin dock connector; 3.5 mm stereo headphone minijack; video out up to 1024 × 768 with the Dock Connector to VGA Adapter (sold separately)USB-C with charging, DisplayPort and USB 3 (up to 10Gb/s); video out up to 4K HDR
PositioningAssisted GPS; digital compass; Wi-Fi; cellularPrecision dual-frequency GPS (GPS, GLONASS, Galileo, QZSS, BeiDou and NavIC); digital compass; iBeacon micro-location

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