Field of application: 3" Supertrapp HD Internal Disc Systems or Off Road IDSX and IDS2 Mufflers
Closed End Cap: Direct Replacement used on 3" Supertrapp HD Internal Disc Systems or Off Road IDSX and IDS2 Mufflers.
Open End Cap: The flow area of the open end cap is the same as 6 3" Discs. Only for Off-Road-Use or Race Tracks!