Oura - Ring 5 - Smart Ring - Size Before You Buy with OR5 Sizing Kit - Size 11 - Silver - (2026) vs Ring AIR Size 5 - Worlds Lightest Sleep-Tracking Wearable - Aster Black (No Monthly Subscription), Adult Unis: which is safer?

Oura - Ring 5 - Smart Ring - Size Before You Buy with OR5 Sizing Kit - Size 11 - Silver - (2026) is the clear pick. Ultrahuman Ring AIR Size 5 - Worlds Lightest Sleep-Tracking Wearable - Aster Black (No Monthly Subscription), Adult Unis carries a failing PFAS grade, and we never recommend buying a failing product.

Our pick

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

Ultrahuman

Ring AIR Size 5 - Worlds Lightest Sleep-Tracking Wearable - Aster Black (No Monthly Subscription), Adult Unis

PFAS grade

F 50/100

Overall grade

F 34/100

Verdict

Skip

Hazard flags

⚑ 4

Material

Titanium alloy body, unknown surface coatings

Confidence

35%

PossibleSurface coating composition and durability

PossibleNickel or trace heavy metals in alloy

PossibleSkin sensitization from prolonged contact

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