| Battery life during active use | At least 6–8 hours with audio, sensors, or display enabled | Supports a full training session, race, or long outdoor ride without interruption. | Test with music, wireless connection, and the main smart functions active at normal volume or brightness. | Essential |
| Charging time and charging case | Full charge in approximately 1–2 hours; case provides at least one additional charge | Fast recovery between workouts is useful when access to a power outlet is limited. | Check whether the case uses a standard USB connection and whether charging can be completed before training. | High |
| Wireless connectivity | Bluetooth 5.0 or newer with stable low-energy operation | Improves connection stability with smartphones, watches, heart-rate sensors, and earbuds. | Walk 8–10 meters from the phone and check for audio dropouts or delayed notifications. | Essential |
| GPS and activity tracking | Built-in multi-constellation GPS, or reliable phone-assisted GPS | Enables route recording, distance measurement, pace tracking, and navigation support. | Compare recorded distance and route accuracy with a trusted sports watch or phone. | High |
| Smart notifications and controls | Call alerts, message previews, music control, and customizable touch or voice commands | Reduces the need to reach for a phone while running, cycling, or training outdoors. | Test controls with gloves, sweaty fingers, and during movement. | High |
| Audio quality and wind resistance | Open-ear or directional audio with clear speech and effective wind-noise reduction | Maintains situational awareness while allowing music, coaching cues, or calls. | Listen and make a call in moderate wind while keeping traffic and environmental sounds audible. | High |
| Display or heads-up information | Readable data such as pace, speed, turn prompts, or notifications in bright and low-light conditions | Allows quick access to essential data without looking down at a phone or wrist device. | Check readability in direct sunlight, shade, and while wearing a helmet or sweatband. | Optional |
| Water and sweat resistance | At least IPX4 for general exercise; IPX5 or higher for heavy rain and intense training | Protects electronics from sweat, splashes, and changing outdoor weather. | Confirm the official rating and avoid immersion unless the manufacturer explicitly permits it. | Essential |
| Fit, weight, and stability | Lightweight construction, secure temple grip, and balanced weight distribution | Prevents slipping, pressure points, and distraction during high-impact movement. | Wear for at least 30 minutes and perform running, head turns, and cycling-position checks. | Essential |
| Lens and visibility options | UV protection, impact-resistant lenses, and interchangeable or photochromic options | Improves comfort and visual clarity across changing light conditions. | Check UV protection, glare control, optical clarity, and compatibility with prescription lenses. | High |
| App compatibility and data export | Compatibility with major mobile operating systems and common fitness data formats | Makes it easier to review workouts and combine data from different sports devices. | Check synchronization, privacy controls, firmware updates, and export options before purchase. | Medium |
| Safety and privacy controls | Visible recording indicator, microphone controls, data permissions, and distraction-free modes | Helps protect personal data and supports safer use around traffic and other people. | Review privacy settings and confirm that recording, microphones, and notifications can be disabled quickly. | Essential |