A new glass production process born out of eyeglass technology has made the filter glass four times stronger, says Yuji Nakano, General Manager of the Hoya Filter Division. Hoya does strength tests by dropping a steel ball on the filters to see how much force will make them break. Also, a new over coating, laid down on top of the more-standard multi-coating, creates an exceedingly smooth surface on the glass for easier cleaning and it repels both water and oil. If you try to write on the filter (as we did) with a water- or oil-based marker, the writing beads up, just waiting for you to wipe it away with a pass of a cleaning cloth. When we tried that with a regular filter…well…we won’t be using that one anymore.