
Polar H9
Score: 83/100
Xiaomi Smart Band 9 Active
Score: 80/100Rankings

The Polar H9 is a chest-mounted ECG heart-rate sensor offering exceptional accuracy and a 400-hour battery life. Its main trade-off is the lack of onboard storage and reliance on a replace-once coin cell battery. Ideal for athletes who need precise data across multiple sports and appreciate dual-protocol connectivity.

The Xiaomi Smart Band 9 Active is a lightweight fitness tracker offering up to 18 days of battery life and a comprehensive set of health sensors. It lacks built-in GPS and its TFT display is less vibrant than AMOLED rivals. Ideal for casual users seeking long endurance and basic tracking.
| Attribute | ![]() | ![]() |
|---|---|---|
400 hours | 432 hoursbest | |
| ↓ lower better | 60 g | 30 gbest |
— | 1.47 inbest | |
— | 50best |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Battery & Power(1) | ||
Battery Life (hours) | 400 hours | 432 hours |
Build & Design(3) | ||
Weight (g) | 60 g | 30 g |
Water Resistance (IP Rating) | IP68 | 5 ATM |
Strap Material | Polyamide/Polyurethane/Elastane/Polyester | TPU |


Products in the top-left offer the best value (high score, low price).

Editors and CrossFit-focused reviewers consider the Polar H9 the best-value chest strap, emphasizing its precise ECG tracking, dual-protocol connectivity, and underwater capability.

Professional reviewers commend the band's ultra-light design, smooth 60 Hz display, long 18-day battery, and solid 5 ATM water resistance, describing it as a valuable upgrade for everyday use. However, they criticize the TFT screen's lower vibrancy, the absence of auto-brightness, and the lack of advanced sensors like GPS or ECG, noting it falls short of higher-end competitors.
Everyday users praise the long battery life, lightweight comfort, smooth scrolling, and the variety of watch faces, finding it reliable for basic fitness tracking. Common complaints focus on the less vivid TFT screen, manual brightness control, occasional heart-rate inaccuracies, and the missing built-in GPS for outdoor activities.