Bemco Reinforced Air Duct Hose. 2-1/4 ID x 20″ OAL. Mil-Spec. NSN 4720-01-166-67751 Inch Hose, 29″ Long. Used on Boeing Aircraft…specs follow: MRC Parameter Characteristics AAGR Cross-Sectional Shape Style Round AARX Inside Diameter 2.250 inches nominal first end AHNC Connection Style Oval first end AWLS Connection Type Soft first end CBBL Features Provided Abrasion resistant CRXX Measuring Method AND Length 20.500 inches nominal overall MATT Material Fiberglass all plies and rubber chloroprene class cr all plies STYL Style Designator Helically wound continous wire supported These would be great for Race Car ducting, air intakes, brake or cooling plumbing. 10234 R3C8