Twice the surface area, half the work say Funnelweb.

Here's their info

Performance and reliability is crucial while riding in off-road conditions.
When designing the Ducati Desert X air filter we aimed to address any possible shortcomings of the standard air intake set-up and produce an element that would withstand the sand, dirt and dust encountered during serious adventure riding.

In addition to our Pyramid profile foam found across the entire FWF range, the DesertX filter boasts a host of Adventure-specific features:

• External foam gasket ensures a positive, air-tight seal preventing any dirt or debris bypassing the filter and entering the air box. 
• One-piece filter cartridge has ample rigidity for support in the air box and enough flexibility to enable hassle-free cleaning and oiling.
• Lower, open pore foam layer firmly locates and seals the cartridge in the air box and effectively acts as a back-up filter, providing an extra layer of protection without impeding air flow.
• Pyramid profile foam pad supplies vital extra filter surface area to trap and hold more dust enabling extended filter service intervals.

PLEASE NOTE: THE ADDITION OF THIS FOAM GASKET REQUIRES THE AIR BOX LID TO BE REMOVED COMPLETELY AND REFITTED ON TOP OF THE AIR FILTER FOR CORRECT INSTALLATION.

Designed and manufactured in Australia, utilising the latest technologies in open cell foam 3D profiling, the pyramid profile effectively doubles the filters outside surface area without increasing its overall size and, compared with conventional foam air filters. Pyramid profile is designed to:

Foam Profile:

• Provide a 100% larger surface area
• Trap dust evenly over the increased outside surface area while allowing optimum airflow
• Maintain optimal airflow by spreading dust build over an increased surface area
• Effectively reduces the frequency of filter changes and cleanings