EXHAUST DOES NOT WORK ON DUROMAX ENGINE 16HP OR 18 HP DO NOT ORDER IT IF YOU HAVE ONE OF THESE ENGINES! Note:This header does not have any kind of paint. Type of material: mild steel, Uncoated Steel. ***Please read before you make your purchase*** If you are buying this for a mini bike please be sure to take measure to ensure that you will not burn your leg.Pipe Diameter. OD: 1.25" ID: 1 1/8" Tube with 1/16 wall >> 2 bolts included and 2 washers. -Gasket not included. -Engine not included. This is custom made Header, weighs about 30oz. Center hollow to hollow 2" (please look all The picture for details) Remember this is not a Muffler, is loud! This is not legal for the streets! Reaches a temperature between 200-700F "heavy duty" This been tested on 8HP (301cc) OHV predator, and Predator 13 HP (420cc) engine from harbor freight. -Works also: GX 270 & 389, Briggs 1450 305cc, Lifan LF190F-BQ 15 HP 420cc Made in U.S.A.