K&F Concept Nano-X Series MCUV Filter vs WR UV Filter: which is safer?

Sigma WR UV Filter is the clear pick. K&F Concept Nano-X Series MCUV Filter carries a failing PFAS grade, and we never recommend buying a failing product.

3M

K&F Concept Nano-X Series MCUV Filter

PFAS grade

F 50/100

Overall grade

F 28/100

Verdict

Skip

Hazard flags

⚑ 4

Material

Optical glass with unspecified coatings

Confidence

45%

PossibleCoating leachables and degradation

PossibleUV-induced coating breakdown

PossibleHydrophobic/oleophobic treatment composition

Why this grade

Our pick

Sigma

WR UV Filter

PFAS grade

A 100/100

Overall grade

A 96/100

Verdict

Buy

Hazard flags

⚑ 1

Material

UV-absorbing optical glass or mineral coating

Confidence

72%

PossibleOptical coating degradation and microabrasion

Why this gradeBuy

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 camera & lens protection: see the full ranking