DNA Stage 2 Air Box Filter Cover for the KTM Duke 690 This S2 Air Box Filter Cover features DNA's advanced FCd (Full Contour design). Installation info are included with this new DNA Stage 2. A specially made Laser cut supporting frame is included with the DNA filter. The filtering efficiency is extremely high at 98-99% filtering efficiency (ISO 5011), with 4 layers of DNA Cotton.The flow of this new DNA Stage 2 Air Box Filter Cover (P-KT6SM13-S2) combined with the DNA Stage 1 Air Filter (P-KT6SM13-01) is very high, 122.36% more than the KTM stock application. DNA S1 & S2 Fcd air filter flow: 248.60 CFM (Cubic feet per minute) @10"H2O corrected @ 25 degrees Celsius. KTM stock paper filter: 111.80 CFM (Cubic feet per minute) @10"H2O corrected @ 25 degrees Celsius. Kit doesn't include Stage 1 filter (sold separately). TECHNICAL FEATURES Drop-In Hassle Free Installation (simply follow the information in the workshop manual) Lifetime Warranty FITS 690 DUKE (2012+) 690 DUKE ABS (2013+) 690 DUKE R / ABS (2012+)