Black anodized billet aluminum with a Contrast Cut machined finish. The Ness Monster Sucker air cleaner comes with the largest filter surface area of all aftermarket 90° air cleaners, which translates to: 'The best breathing 90° air cleaner on the market!' It allows this filter to keep-up with air-demands from bone stock all the way up to massive horsepower spitting engines. Filter elements are constructed from oiled high flow cotton gauze filtering material. The aluminum body is manufactured from precision forged billet aluminum and CNC machined to the Ness standard where perfection is absolute. Hidden patented internal breathers are used to provide efficient breathing combined with the cleanest looks. Note: An optional rain sock is separately available as 590443, for when riding in adverse weather conditions.