Apple Watch Series 4 (GPS + Cellular) 44mm in Space Black stainless steel remains a notable option in the wearable technology market, combining advanced health monitoring features with cellular connectivity for users seeking independence from their iPhone. Released in September 2018, this model introduced significant upgrades over its predecessors, including a larger display, faster processor and enhanced sensors that laid the groundwork for future innovations in Apple’s wearable lineup.
The 44mm variant features a stainless steel case with a Space Black finish achieved through diamond-like carbon (DLC) coating, paired with a Retina LTPO OLED display offering 1000 nits of brightness and a resolution of 368 by 448 pixels. This results in a display area of 977 square millimeters, providing ample space for complications, notifications, and fitness tracking interfaces. The device is powered by Apple’s S4 SiP with a 64-bit dual-core processor, delivering up to twice the performance of the S3 chip found in earlier models.
One of the most significant advancements in the Apple Watch Series 4 was the introduction of an electrical heart sensor capable of generating an electrocardiogram (ECG) similar to a single-lead reading. This feature, combined with the improved optical heart sensor, enabled users to monitor for signs of atrial fibrillation (AFib), marking a major step in consumer-focused preventive health technology. The ECG app and irregular rhythm notification feature received clearance from the U.S. Food and Drug Administration (FDA) prior to launch, underscoring Apple’s collaboration with regulatory bodies to validate health-related claims.
Connectivity options include LTE and UMTS for GPS + Cellular models, allowing users to craft calls, send messages, and stream data without relying on a paired iPhone, provided both devices are subscribed to the same wireless carrier. The watch also supports Wi-Fi (802.11b/g/n 2.4GHz) and Bluetooth 5.0 for seamless integration with Apple’s ecosystem. A built-in rechargeable lithium-ion battery provides up to 18 hours of typical use, recharged via magnetic charging cable and USB power adapter.
Water resistance is rated at 50 meters under ISO standard 22810:2010, making the Apple Watch Series 4 suitable for swimming in pools or open water, though Apple advises against use for scuba diving, waterskiing, or other high-velocity water activities. The device incorporates a barometric altimeter for elevation tracking, an improved accelerometer capable of measuring up to 32 g-forces, and a gyroscope for enhanced motion detection in fitness and navigation applications.
Available case materials for the Series 4 included stainless steel (Silver, Space Black, Gold), aluminum (Silver, Space Gray, Gold), and ceramic (limited to Hermès editions). The 44mm stainless steel model weighs approximately 47.9 grams, while the aluminum version of the same size is lighter at 36.7 grams. Storage capacity is fixed at 16GB, sufficient for storing apps, music, and health data locally.
Apple Watch Series 4 models run watchOS 5 at launch, with support for subsequent updates up to watchOS 9, ensuring access to newer features such as improved workout metrics, mindfulness tools, and enhanced Siri functionality over time. The device is compatible with iPhone 6s or later running iOS 12 or higher, maintaining broad accessibility within Apple’s mobile ecosystem.
For users considering a pre-owned Apple Watch Series 4 (GPS + Cellular) 44mm in Space Black stainless steel, verifying the device’s operational status, battery health, and activation lock status is essential. Potential buyers should confirm that the watch has been unpaired from any previous iCloud account and is ready for setup. Authorized resellers and certified refurbishers often provide warranties and quality assurances that private sales may lack.
While newer models like the Apple Watch Series 8 and Ultra 2 offer features such as temperature sensing, crash detection, and dual-frequency GPS, the Series 4 remains a capable device for core health tracking, notifications, and fitness monitoring. Its enduring relevance speaks to the longevity of Apple’s hardware design and software support strategy, particularly for users prioritizing essential smartwatch functionality at a reduced cost.
As wearable technology continues to evolve with deeper integration into personal health management, the Apple Watch Series 4 stands as a milestone in bringing clinical-grade heart monitoring to the consumer market. Its influence can be seen in the continued emphasis on preventive care features across competing platforms and subsequent Apple Watch generations.
For official specifications, software updates, and support documentation, users can refer to Apple’s support portal. Those interested in trading in or recycling older devices may explore Apple’s trade-in program for credit toward new purchases.
What are your experiences with the Apple Watch Series 4? Share your thoughts in the comments below, and feel free to pass this article along to others interested in wearable technology and health-focused smartwatches.