K&N Custom 66 Series custom air cleaner assemblies are designed for use with any engine that uses a round element air cleaner housing. K&N Air Filters provide serious air flow. Each complete assembly comes with base, element, top plate and stud.

Billet Aluminum Spoked Lid Assemblies
These 14” assemblies feature a billet aluminum lid with spokes and a carbon fiber insert.  They include the popular 4” tall E-3750 replacement round filter.

Part 66-5090 Product Specifications
Product Style: Custom Assemblies
Color: Red
Filter Height: 4 in (102 mm)
Filter Material: Cotton Gauze
Neck Flange: 5.125 in (130 mm)
Overall Height: 4.625 in (117 mm)
Replacement Filter: E-3750
Size: 14 Inch
Style: 1-1/4" Drop Base
Top Material/Finish: Aluminum
Top Style: 5 Spoke Billet Aluminum
Total Height: 4.625 in (117 mm)
Weight: 9.8 lb (4.5 kg)

See here for more info: http://knfilters.com/racing/custom66.htm