Helio Smart Ring Health Tracker vs Ring 4 Ceramic Smart Ring with 8-Day Battery: which is safer?

Where these two actually differ

• We flag Polymer band composition and residual monomers and Bacterial growth in sealed band-case junction on the Amazfit and not on the Oura.
• We flag Ceramic coating degradation and Nickel in titanium alloy on the Oura and not on the Amazfit.
• The Amazfit is Titanium alloy case, polymer band where the Oura is Titanium and ceramic composite ring, which is most of the difference in these two grades.
• These two are level, close enough that price and fit should decide it rather than our grade.
• We are less certain about the Amazfit grade, at 35% confidence against 72%, because it discloses less.