Double side 18-Layer super anti-reflection multi-coated, 99% of transmittance. Super water resistant, stain & scratch resistant, mildew-proof and antibacterial steel coating film ultra hardness prevents fragile optical glass and surface coating film from damage. Ultra thin low profile frames to help avoid vignette on super wide angle lens.Ultra thin Glass: 1.1mm and Filter frames: 3.1mm.Knurling Edge Frame: These filters are equipped with a straight knurling edge for non-slip, easy attachment and removal.All Materials Used in this filter Meet the Requirements of European Union’s standards of Environ Ment Protection-ROHS(Restrictions on Hazardous Substances).