"DESIGNED SPECIFICALLY TO FIT WITHNORDIC POSI-VENT ONLY, THE HOOD CLAMPSTO THE 8-3/8 INCH POSI-VENT OUTER FLANGE OF THE MECHANICAL COMPARTMENT VENT,MADE FROM CAST ALUMINUM, COMES WITH BUNA GASKET AND STEEL RING CLAMP FOR FLANGE MOUNTING, MACHINED BASE FOR TIGHT GASKET SEAL MOUNTING"