Oura - Ring 5 - Smart Ring - Size Before You Buy with OR5 Sizing Kit - Size 11 - Silver - (2026) vs 2025 New! Xiaomi Smart Ring for Men & Women. Tracks Heart Rate, Blood Oxygen, Sleep. 5ATM Waterproof Fitness Tracker Pin: which is safer?

Oura - Ring 5 - Smart Ring - Size Before You Buy with OR5 Sizing Kit - Size 11 - Silver - (2026) is the clear pick. 2025 New! Xiaomi Smart Ring for Men & Women. Tracks Heart Rate, Blood Oxygen, Sleep. 5ATM Waterproof Fitness Tracker Pin carries a failing PFAS grade, and we never recommend buying a failing product.

Our pick

Oura - Ring 5 - Smart Ring - Size Before You Buy with OR5 Sizing Kit - Size 11 - Silver - (2026)

Fitbit

Oura - Ring 5 - Smart Ring - Size Before You Buy with OR5 Sizing Kit - Size 11 - Silver - (2026)

PFAS grade

B 85/100

Overall grade

D 67/100

Verdict

Buy

Hazard flags

⚑ 3

Material

Titanium and stainless steel with glass sensor

Confidence

72%

PossibleElectronic component off-gassing or thermal breakdown

ReportedBiofilm and bacterial growth on sensor surfaces

PossibleGlass or metal micro-debris from wear

Why this gradeBuy
2025 New! Xiaomi Smart Ring for Men & Women. Tracks Heart Rate, Blood Oxygen, Sleep. 5ATM Waterproof Fitness Tracker Pin

Xiaomi

2025 New! Xiaomi Smart Ring for Men & Women. Tracks Heart Rate, Blood Oxygen, Sleep. 5ATM Waterproof Fitness Tracker Pin

PFAS grade

F 40/100

Overall grade

F 10/100

Verdict

Skip

Hazard flags

⚑ 4

Material

Metal alloy ring with unspecified waterproof coating

Confidence

32%

PossibleNickel leaching from metal alloy

LikelyUndisclosed waterproof coating (possible PFAS)

PossibleCoating degradation and flaking

Why this grade

Both products run through the same public rubric: materials, coatings, brand disclosure, lab findings, and recalls, plus a beyond-PFAS hazard analysis. Grades are model-based estimates, not lab tests. How grades work →

More waterproof smart rings & bands: see the full ranking