Russell 640221 Endura -6AN Carburetor Adapter Fitting - Pack of 2 Lightweight aluminum fittings are designed to match up with all Russell performance hose and hose ends 37 degree sealing angle guarantees a positive seal at maximum operating pressures Fits best to Dual Feed Holley 750 through 1350 Dominator Precision machined to ensure precise thread engagement Coupler size is -6 AN