Glen asked me if I could come up with a 3D printed approach to installing a prefilter on the intake of his CB500X. The idea is to extend the life of the bike's own air filter when the bike is used in dusty conditions. The space behind the air filter is quite limited even after Glen had removed the snorkel. My idea was to put a kind of flange on the cover of the air filter that attaches to it using the same mounting screws as was used to secure the snorkel. The filter is a swimming pool skimmer sock. The socks are cheap - cheap enough to dispose of after use. The advantage of the sock is that it takes up no space outside the air filter cover because it goes inside the filter. The elastic cuff of the sock goes over the flange and holds it in place. The sock "inflates" on the inside of the filter to conform to its internal shape. 

Glen did a video on its installation and function: