Waterproofing Wax for Leather vs Multipurpose Fabric Shield Water & Stain Protector Spray: which is safer?

Where these two actually differ

• We flag Respiratory irritation or fume inhalation during application and PFAS in water repellency treatment on the Nikwax and not on the Flex Seal.
• We flag Inhalation of aerosolized coating compounds, Skin and eye irritation from spray drift, Coating degradation and wear particle release and Water and soil repellent efficacy loss requiring reapplication on the Flex Seal and not on the Nikwax.
• The Nikwax is wax-based waterproofing where the Flex Seal is Proprietary water and stain repellent coating, composition not disclosed, which is most of the difference in these two grades.
• The gap is 25 points, wide enough that this is not a close call, and the Nikwax is the one to buy.
• We are less certain about the Flex Seal grade, at 35% confidence against 78%, because it discloses less.