This hose assembly attaches to the back of the of the compressor, connecting it to the POA valve (including the specialized "Sheppard's Hook" fitting) at the firewall and the top fitting of the condenser in front of the radiator support. Made of all new components, including barrier hose that is compatible with both R12 & 134a refrigerants. NOTE - This is not a judging correct replacement hose that is specific to either big-block or small-block. Many of the car's original hoses came with a muffler built into the manifold that this hose assembly does not have. This can be used as a direct replacement with no modification whatsoever.