عنصر أنبوبي صلب يناسب بين المحمل وغطاءه، تم تصميمه في المقام الأول كسطح تآكل قابل للاستبدال داخل الجدار الداخلي للغطاء.
"99167-c+16.03 specification (includes engineering type bulletins, brochures,etc., that reflect specification type data in specification format; excludes commercial catalogs, industry directories, and similar trade publications, reflecting general type data on certain environmental and performance requirements and test conditions that are shown as "typical", "average", "nominal", etc.)." test data document, steel,qq-s-763,cl 321; 3.1850 in. min and 3.1950 in. max body id; 3.4574 in. min and 3.4577 in. max body od; 3.7140 in. min and 3.7240 in. max external flange od;0.0750 in. min and 0.0850 in. max external flange thickness;internal flange on opposite end of external flange; 3.0750 in. min and 3.0850 in. max internal flange id; 0.1020 in. nomminal internal flange thickness; 0.6200 in. min and 0.6400 in. max overall length; knurl starting 0.0600 in. max below external flange on body outside surface,0.0980 in. min and 0.1580 in. max in length; passivate,cp 14.10-03,99167,o/a; 250 microinches surface finish on left end surface of body and flange,and right end surface of left flange general characteristics item description