Apple Watch Ultra 4 / Apple Watch Series 6 (40 mm, GPS)

Apple Watch Ultra 4: A3579; 49 mm natural titanium; translucent gray Ocean Band

Apple Watch Series 6 (40 mm, GPS): Apple Watch Series 6, 40 mm aluminium case, GPS (2020). The 44 mm and GPS + Cellular versions, stainless steel/titanium cases and the Nike and Hermès editions are separate.

SpecificationApple Watch Ultra 4Apple Watch Series 6 (40 mm, GPS)
Release year20262020
Announcement / availability9 / 18 September 2026 Apple—
CaseGrade 5 titanium; sapphire front crystal Apple—
Size49 × 44 × 12 mm Apple—
WeightNatural titanium case 63 g Apple—
DisplayLTPO3 OLED; 422 × 514 AppleAlways-On Retina LTPO OLED; 324 × 394 pixels, 759 mm² display area; 1000 nits

The Always-On display keeps the time and complications visible with the wrist down.

Apple
Brightness1 nit minimum; 3000 nits peak Apple—
ChipS11; dual-core 64-bit AppleS6 SiP with 64-bit dual-core processor; W3 wireless chip; U1 Ultra Wideband chip

Ultra Wideband availability varies by region.

Apple
Storage64 GB Apple32 GB Apple
Health sensorsElectrical/optical heart; blood oxygen; temperature AppleBlood oxygen sensor (Blood Oxygen app), electrical heart sensor (ECG app), third-generation optical heart sensor

Apple states Blood Oxygen measurements are not for medical use and are only designed for general fitness and wellness. The ECG app is not intended for people under 22.

Apple
Outdoor sensorsDepth, water temperature, compass, altimeter Apple—
PositioningPrecision dual-frequency GNSS Apple—
WirelessWi-Fi 4, 2.4/5 GHz; Bluetooth 5.3; UWB AppleWi‑Fi 802.11b/g/n 2.4 and 5 GHz; Bluetooth 5.0

LTE and UMTS are only on GPS + Cellular models.

Apple
CellularA3579: 5G RedCap and LTE Apple—
Manufacturer battery testUp to 50 hours normal use; 84 in Low Power Mode Apple—
ChargingAbout 45 minutes to 80% Apple—
Water / dust100 m rating; IP6X Apple—
Diving limitRecreational diving to 40 m Apple—
Phone compatibilityiPhone 11 / SE 2 or later; iOS 27+ Apple—
Case and version—40 mm aluminium case, GPS; Silver, Space Gray, Gold, Blue, (PRODUCT)RED

Stainless steel and titanium cases were only sold in the GPS + Cellular version. The 44 mm model uses the same chip but has a different display and weight.

Apple
Water resistance—50 metres (ISO 22810:2010)

Suitable for shallow-water swimming in a pool or the sea, but not scuba diving, waterskiing or high-velocity water.

Apple
Other sensors and safety—Always-on altimeter, compass, accelerometer up to 32 g with fall detection, gyroscope, ambient light sensor; Emergency SOS

On the GPS model, Emergency SOS needs the iPhone nearby; otherwise the watch must be on a known Wi‑Fi network with Wi‑Fi Calling on. International emergency calling is only on the cellular model.

Apple
Battery and charging—Built-in lithium-ion battery; up to 18 hours; magnetic charging cable (1 m)

The 18-hour figure comes from Apple’s August 2020 testing with pre-production watches paired to an iPhone; it varies with use.

Apple
Other—Speaker, microphone, Apple Pay, GymKit; ceramic and sapphire crystal back Apple
Compatibility—Requires an iPhone 6s or later with iOS 14 or later Apple
Size and weight—40 × 34 × 10.7 mm; 30.5 g (aluminium, without band) Apple