The pipe is stainless steel 304 including hardware. 1" Common FEMALE Pipe Thread, Measures approximately 6.75" long... see photo for better detail. (This exhaust does not work on XP16HPE, XP18HPE engines 16 or 18hp! ) Center hollow to hollow 2" (please look all The picture for details) This been tested on 8HP (301cc) OHV Predator & Predator 13 HP (420cc) Works also: GX 240, 270 & 390, B&S 1450 305cc, Lifan LF190F-BQ 15 HP 420cc Made in U.S.A.