This is a very high quality US Made 637432 brake line tee. This is the tee located on both the front and rear axle. The brake hose from the frame attaches to this and the metal lines leading to the wheel cylinders do as well. This is all brass construction. NOTE: these will work on the M38 and M38A1 but their original tees had an angle built into them which pushed the hose inlet out away from the axle.